849 Sentences With "dorsal fins" | Random Sentence Generator

His gloves sometimes have wings of leather, like dorsal fins.

The report included documentation of individual sharks by their dorsal fins.

Late at night, the ids of his callers and guests flash like dorsal fins.

Think of them as "oversized dorsal fins," NASCAR says, getting in the way of the air.

They also have more rounded heads and pointier dorsal fins compared to Type A, B, and C orcas.

"You see skin, you see dorsal fins literally sticking straight up in the sediments, species new to science," he said.

So next time you hop on the river for a canoe ride, you might want to watch for dorsal fins.

In the moonlight while treading water to keep afloat, he could make out the dorsal fins of two blue sharks circling him.

It's not easy to understand the sixgills, though Grubbs has glimpsed the sharks' mysterious existence by tagging their dorsal fins with GPS devices.

So to find out what the sharks truly were doing during lunchtime, he and his team attached sensors and cameras to their dorsal fins.

The scientists also looked for other characteristics that might be indicative of oil exposure, such as fetal folds, creased dorsal fins, rostral hairs (near the mouth), and dental eruption.

He's dived with thousands of whale sharks and knows some of them personally by marks on their bodies, missing dorsal fins, propeller scars from big ships, and tags from researchers.

From there, they planned to ski onto Messner Glacier in western Antarctica and climb into a crosswind from sea level toward the Thiel Mountains, which rise like dorsal fins above an otherwise unbroken sea of snow and ice.

The lionfish's brightly colored stripes and flowing pectoral fins may look beautiful but its dorsal fins pack a venomous punch, its sting is toxic, it spawns up to 30,000 eggs every four days and feasts on other fish and crustaceans.

With their fearsome teeth and dorsal fins the inspiration for hit movies, TV series and beach-town souvenirs, it is hard to believe that a century ago American scientists did not believe sharks would fatally attack humans in U.S. temperate waters without provocation.

Because the shirt is covering the dolphin's dorsal fin, the wildlife officers can't tell if the animal was previously tagged, nor can they identify it from a set of local dolphin photos (dorsal fins are like fingerprints—no two are the same).

In the clip the missile appears to have slim dorsal fins, foldable tail fins and additional propellant, all of which, according to one expert who asked not to be identified, suggests it is designed to fly long distances and faster than the speed of sound.

One day, when our beach was closed because of violent rip currents, my son's group learned about the stonefish — that's the one that looks like a rock but is the most venomous fish around, with spiky dorsal fins that will inject poison into your feet if you step on one.

Growing up to 2.5 meters (8.2 feet) in length, with short, stubby snouts and small dorsal fins high up on their arched backs, pink dolphins have lived in the waters around Hong Kong for hundreds of years, as the human population grew from the low thousands in the 1600s to the millions today.

Breeding males have light orange edges on their dorsal fins.

Male Pacific leaping blennies have prominent head crests and orange-red dorsal fins.

The little gulper shark has no anal fin, two dorsal fins with spines, slightly humped back before the first dorsal fin, darker areas of coloration above gills and on dorsal fins, long free rear tips on pectoral fins, and a notched caudal fin.

Redspotted catsharks have two dorsal fins, with the first dorsal axil over the pelvic region. Their dorsal fins do not have spines, and their tails have no upward bend. Redspotted catsharks have multicuspid teeth. However, males typically have longer teeth with fewer cusps.

Juveniles are occasionally used in saltwater aquariums, noted for their filamentous anal and dorsal fins.

Pacific Barracuda have a distinct feature of a forked tailed fin and widely separated dorsal fins.

Monodactylidae is a family of perciform bony fish commonly referred to as monos, moonyfishes or fingerfishes. All are strongly laterally compressed with disc-shaped bodies and tall anal and dorsal fins. Unusually for fish, scales occur on their dorsal fins and sometimes on the anal fins. The pelvic fins are small, sometimes vestigial.

At the base of their pectoral and dorsal fins are spines, which they can use as spurs to cut predators.

The fish is a yellowish colour, being darker above with a diffuse silver longitudinal mid-lateral band on the sides. All fins are hyaline in appearance, with the dorsal fins being dusky with a narrow blackish margin. Juveniles have a series of small brown spots along their back at the base of the dorsal fins.

Males also usually have brighter and more vivid colors. For most breeds, the females have black dots on their dorsal fins, whereas males usually have longer anal and dorsal fins. Females tend to have an orange belly, especially when ready to breed. The mouth of the male is thicker and more pronounced than the female's.

The anal and dorsal fins of the striped nothobranch have no spines, but, respectively, 16-18 and 11-17 soft rays.

Makaira mazara can reach a maximum length of , but the average is around . It can reach a weight of about . Body is elongated but it is not very compressed, with two dorsal fins and two anal fins. Dorsal fins have a total of 40 to 45 soft rays, while anal fins have 18 to 24 soft rays.

3rd ed. 368 p. hence the name bonnetmouth. They usually have 14-15 spines on their dorsal fins, but only 10 soft rays.

There are two dorsal fins. The species can be identified by the arrangement of pores on its head, the spines and rays in the dorsal fins, and the scales and papillae on the head and face. The yellow ventral fins also distinguish it from other gobies. The lifespan is generally up to 3 years, but some individuals may get older.

They also have two dorsal fins spaced widely apart, which help identify the species in the open ocean. In front of each pectoral fin is one single gill opening. Between the two dorsal fins is a spine, and the second dorsal fin is significantly smaller than the more anterior one. The caudal fin is divided into two lobes, the top one being larger.

In balistiform locomotion, both anal and dorsal fins undulate. It is characteristic of the family Balistidae (triggerfishes). It may also be seen in the Zeidae.

It has two variably marked dorsal fins, along with two pectorals and an anal fin.Warfel and Merriman (Copeia, 1944, p. 198)Cox, Contrib. Canadian Biol.

The dorsal fins have 9 dorsal spines and 10 soft rays, whereas the anal fin has three anal spines and seven or eight soft rays.

The mouth is wide, with relatively short furrows at the corners, and contains small multi-cusped teeth. There are five pairs of gill slits. The first and second dorsal fins are similar in size and shape, and are placed mostly behind the pelvic and anal fins respectively. The space between the dorsal fins is much longer than the length of either dorsal fin base.

Their body shape is elongate and narrow and lacks a lateral line. Northern studfish have spineless fins and both the anal and dorsal fins are large.

This fish reaches a maximum length of TL. This fish's neck is scaled and both of its dorsal fins have a black spot on the front end.

The genus is characterized by a broad dark blue stripe along the side. The genus has large anal and dorsal fins, as well as a compressed body.

This genus is most closely related to the genus Bagroides. In turn, these two genera are most closely related to Leiocassis. The genus can be split into two lineages. B. hypselopterus, B. macracanthus, B. majusculus, and B. vaillantii have long dorsal fins with 18 or more serrations in adults, while B. macropterus, B. micranodus, and B. obscurus have short dorsal fins with 15 or fewer serrations in adults.

They superficially resemble members of the genus Acentrogobius, but Oplopomus can be distinguished by having the first rays of both dorsal fins ending in a sharp point (pungent).

It is a black or a very dark brown, uniformly, in color, and lacks an anal fin. It lives from to . The dorsal fins have an associated spine.

The two dorsal fins have a total of 7 spines and 9-10 soft rays 9-10; the anal fin has 2 spines and 8-9 soft rays.

The specific name is derived from the Latin for ‘spotted’, referring to the numerous black spots on the caudal and dorsal fins. It is used as an adjective.

Boga at cleaning station. Note extended mouth. The boga is a spindle-shaped fish. It has a deeply forked caudal fin, and its two dorsal fins are close together.

The pectoral, pelvic, and spinous dorsal fins are hyaline to dusky, while the second dorsal fin is yellow distally. The caudal and anal fins are yellow to dusky yellow.

The stripetail darter males are golden orange and as adults can grow up to long. It also has black bands present on the caudal fins and soft dorsal fins.

The longbill spearfish is a blueish black color from above, and silvery-white and brown on the sides. The pectorals are blackish-brown and the dorsal fins are dark blue.

The teeth are sharp and these fish can be told from the rather smaller brook lamprey (Lampetra planeri) by the fact that the two dorsal fins are more widely separated.

Its scales are minute, and the mouth extends beyond to the eye. The dorsal fins have short horizontal stripes and the body is pale brownish-grey in colour with darker mottling.

The smallfin gulper has no anal fin, two dorsal fins with spines, long free rear tips on pectoral fins, and a deeply notched caudal fin. Its maximum length is 98 cm.

There are a total of 4 spines in the dorsal fins and 9 soft rays with 8 soft rays in the anal fin. This species grows to a length of SL.

The belly is creamy or white and wavy lines may appear slightly above the white belly on the sides. The dorsal, caudal and anal fins are dark olive green to grayish black. Pelvic fins may have a cream colored leading edge with dark spots. The shoal bass has scales on the base portion of the soft-rayed dorsal fins, clearly connected first and second dorsal fins, and an upper jaw bone that does not extend beyond the eyes.

Auxis can reach a length of . They have a strong, fusiform body with a sharpened head. The teeth are small and conical. The two dorsal fins are separated by a wide gap.

The two dorsal fins are of comparable size, the first positioned slightly closer to the pectoral than the pelvic fins and the second over the anal fin. The caudal fin is low and long, comprising a quarter of the total length or more, and lacks a lower lobe. The coloration is a plain dark brown, with black markings on the dorsal fins and darker bands on the caudal fin. The maximum recorded lengths are for a male and for a female.

They also have a dark lobe on the posterior part of their dorsal fins. The longest recorded flat needlefish measured 140 cm.IGFA 2001 Database of IGFA angling records until 2001. IGFA, Fort Lauderdale, USA.

Proc Biol Soc Washington 103 (2): 453- 463. Some populations of spinner dolphin found in the eastern Pacific have bizarre backwards-facing dorsal fins, and males can have strange humps and upturned caudal flukes.

Dorsal fins are yellowish with black tips, while the caudal and pectoral fins are yellowish. The remaining fins are dusky. Indian mackerel reach a maximum fork length of , but are generally around in length.

Plethodids possessed thin, angelfish-like bodies and often had high dorsal fins which made them distinctive from other types of fish. Their skeletons were partially cartilaginous, though the amount varied from one species to another.

Males can reach a maximum total length of 16.1 centimetres. The species epithet "trimaculatus" means "three spots" in Latin, and refers to the quantity of spots adorning the anal and dorsal fins of the eel.

Both species are large, slow-moving, bulky sharks inhabiting shallow coastal waters, and can be identified by their short, blunt snouts, two dorsal fins of nearly equal size, and uniform yellowish brown or gray coloration.

The back of the fish is olive-brown and the flanks silvery, with longitudinal dark banding. Juveniles have two longitudinal rows of black spots on the dorsal fins and some dark barring on the sides.

The second dorsal fin is very long and sickle-shaped. The fish grows up to 50 cm long. The second dorsal fin is longer and sickle-shaped. Its dorsal fins have bony, knife-like spines.

Atractosteus fossil Gar bodies are elongated, heavily armored with ganoid scales, and fronted by similarly elongated jaws filled with long, sharp teeth. Their tails are heterocercal, and the dorsal fins are close to the tail.

A. bivittatum has an elongated, brightly coloured body with two dark bands made up of red spots running along each side, with the colors varying between populations. Individual males are commonly found with golden- brown dorsal surfaces, bluish sides, and golden ventral surfaces. The males have a maximum body length of approximately and have brightly marked, tall and pointed anal and dorsal fins that are yellow to pastel green with red edges. The caudal and dorsal fins are green with red spots and bright yellow tips.

The tuna is a sleek and streamlined fish, adapted for speed. It has two closely spaced dorsal fins on its back; The first is "depressible" – it can be laid down, flush, in a groove that runs along its back. Seven to 10 yellow finlets run from the dorsal fins to the tail, which is lunate – curved like a crescent moon – and tapered to pointy tips. The caudal peduncle, to which the tail is attached, is quite thin, with three stabilizing horizontal keels on each side.

An adult moonlight gourami reaches a length of to up SL. These fish are silvery colored with a slightly greenish hue similar to the soft glow of moonlight. The moonlight gourami's concavely sloped head distinguishes it from other gourami varieties. The males can be identified by the orange to red coloration of the pelvic fins, as well as the long dorsal fins which ends in a point. In females, the pelvic fins are colorless to yellow, and the dorsal fins are shorter and rounder.

However, the spotted wobbegong has smaller and less dense dorsal fins, which lack the black markings that the dwarf spotted wobbegong's dorsal fins have, differentiating the two fishes. Therefore, the two wobbegongs are classified as two separate species. The spotted wobbegong has been confused with the Gulf wobbegong (Orectolobus hatei) in New South Wales, but the white marks of the spotted wobbegong, as well as its greater number of dermal lobes, distinguish the two species. It is also frequently confused with the ornate wobbegong (Orectolobus ornatus).

The snout is semi-transparent. The first and second dorsal fins, as well as the caudal fin, are pale with blackish rear margins. The membrane of the pectoral fin is blackish. The pectoral filaments are white.

The dorsal fins are separated with six rays on the first. The ventral fins are joined by a bridge of skin (a frenum). The caudal fins are round. They can grow to a maximum length of .

These spots often run together to form horizontal dashes, which include white tips on the dorsal fins and a white stripe through the gill slits. The underside is plain white. This species grows up to long.

It grows to a length of 9.1 cm, and can have up to 15 dorsal fins, 15 anal fins, 8 pelvic fins, 18 gill rakers, and 35 lateral lines. Their coloring is dark with paler photophores.

The colour is uniform all over the body, with only the tip of the spinous dorsal fins black. Little else is known, including swimbladder morphology and vertebrae numbers. The specimen described was 158 mm in length.

Tiger fish is locally known as Wagassa, and scientifically as Hydrocynus vittatus. It grows up to 105 cm long and 28 kg in weight. It has long gill rakers. The tips of adipose and dorsal fins black.

This mode of locomotion even enables the shark to crawl out of the water to access isolated tidal pools.Martin, R.A. Why Do Sharks Expose Their Dorsal Fins? ReefQuest Centre for Shark Research. Retrieved on October 4, 2009.

Juveniles are more ornately patterned than adults, with pale lines and darker blotches. The dorsal fins have a darker leading margin and lighter trailing margin. Some individuals have a white spot on the back of the "neck".

Notomelia and cephalomelia are atavistic reappearances of dorsal fins. Some other cases of polymelia are extra development along the paired part of the fin lines, or along the ventral posterior non-paired part of the fin line.

Amblygobius sphynx has a total of 7 spines and 13-15 soft rays in its dorsal fins, the anal fin has a single spine and 13-15 soft rays. The background colour on the body is yellowish brown fading to white on the underside. There are 5-6 dark brown bars with white markings between them on the flanks and there is a row of small, widely sparated black spots along the upper back. The first and second dorsal fins are equal in height and the caudal fin is rounded.

The dorsal fins are the most distinctive character: Those of the sailfin molly have less than 15 fin rays, counting where the fin meets the back, whereas the Yucatan molly has 18-19 (intermediate numbers may indicate hybrids). If a male spreads his dorsal fins in a display, in this species it forms a trapezoid, with the posterior edge being shortest. The height of the dorsal fin, measured at the posterior edge, is a bit less than the height of the tail. The male molly is more aggressive than the females.

Unlike any other member of the toadfish family, the splendid toadfish is distinctive for its vibrant colors. It has bright yellow fins which also contain distinctive patterning, while its head contains dark and white stripes. The species has a total of eight fins; two dorsal fins, two pectoral fins, two pelvic fins, a caudal fin and an anal fin. The midline of the upper body contains the two dorsal fins; a short fin with sharp spines in 3 spots and a long fin which extends over much of the upper body and is flowing.

The dorsal fins are the most distinctive character for telling the species apart: Those of the Yucatan molly have nearly 20 fin rays, counting where the fin meets the back, whereas the sailfin molly has less than 15 (intermediate numbers may indicate hybrids). If the males spread their dorsal fins in display, these have a distinct fan or trapezoid shape, with the upper edge being distinctly longer than the lower. The height of the dorsal fin, measured at the posterior edge, is a bit larger than the height of the tail.

The lowfin gulper shark has no anal fin, two dorsal fins (with spines with the first dorsal fin being much longer than the rear), a long, broad snout, and angular pectoral fins. Its maximum length is 1.6 m.

In fact, they are about equal in size. The pectoral fins are triangular and only slightly larger than the dorsal fins. The teeth are very long and narrow with sharp points. The teeth are smooth with no ridges.

Fat sleepers are small fish that have two distinct dorsal fins and scaled, flat heads. Their tails are rounded.Smith, L. C. The Inland Fishes of New York State. New York: The New York State Department of Environmental Conservation.

However, male dragonets can be differentiated from the goby by their very long dorsal fins, and females by their protruding lower jaws. The Draconettidae may be considered a sister family, whose members are very much alike, though rarely seen.

The group consisted of large, triangular- toothed sharks with a ridge between the dorsal fins, and also included the bignose shark (C. altimus), the Caribbean reef shark (C. perezi), the sandbar shark (C. plumbeus), and the oceanic whitetip shark.

The circular bands do not extend onto the ventral surface in the trunk area, but are visible along the tail. The anal, pectoral, and dorsal fins are generally unpigmented, but may have some scattered melanophores. The caudal fin is dusky.

Ariid catfish have a deeply forked caudal fin. Usually, three pairs of barbels are present. They possess some bony plates on their heads and near their dorsal fins. At least some species have venomous spines in their dorsal and pectoral fins.

Teeth and jaw of a female Leafscale gulper shark. The leafscale gulper shark has no anal fin, two dorsal fins with spines, the first dorsal being relatively low and long, large eyes, and rough leaf-like denticles. Its maximum length is .

The eel is up to long. The color is brownish-beige with a ring-shaped dark brown pattern. The dorsal fins are hard. The fish is endemic to Lake Tanganyika and can commonly be found along the shores of the lake.

Males are black during spawning with red anal and dorsal fins. Females have dull coloration consisting of brown and green shades. Dominant males become very aggressive and territorial when spawning. As with other cichlids, their life expectancy is around 10 years.

The roughback sea catfish grows up to 40 cm long. They live in the salty waters of tropical regions of the world. They feed on invertebrates. They have pointed dorsal fins, which can cause injury if held by unprotected human hands.

Australian Museum. Retrieved on 2008-12-01. This species of shark normally grow less than a metre long, but have been known to reach 1.25 metres. C. australis has smaller eyes, pectoral fins, dorsal fins, and spine than its cousin.

The thinlip mullet has an elongate body compressed laterally. The head is short and flattened and the mouth is broad with a narrow upper lip and no tubercles. There are two dorsal fins. It is steely blue above and paler beneath.

They also assert that swordfish "use sensitive rostrum/lateral-line sensors to detect upcoming/ambient water pressure and attain the best attack angle to capture the body lift power aided by the forward-biased dorsal fin to compensate for most of the water resistance power." Billfish have prominent dorsal fins. Like tuna, mackerel and other scombroids, billfish streamline themselves by retracting their dorsal fins into a groove in their body when they swim. The shape, size, position and colour of the dorsal fin varies with the type of billfish, and can be a simple way to identify a billfish species.

It is possible that the sail of Spinosaurus was used for courtship, in a way similar to a peacock's tail. Stromer speculated that the size of the neural spines may have differed between males and females. Gimsa and colleagues (2015) suggest that the dorsal sail of Spinosaurus was analogous to the dorsal fins of sailfish and served a hydrodynamic purpose. Gimsa and others point out that more basal, long-legged spinosaurids had otherwise round or crescent-shaped dorsal sails, whereas in Spinosaurus, the dorsal neural spines formed a shape that was roughly rectangular, similar in shape to the dorsal fins of sailfish.

This species can range from grey to brown in colour and can have dark vertical stripes along its side. It has two dorsal fins and thickened skin on the pelvic fins, which is thought to be an adaptation to allow the fish to rest on the ocean substrate, as it lacks a swim bladder to maintain buoyancy. This species is sexually dimorphic, with the males having longer and darker first dorsal fins than females. At sexual maturation, females (48–49 cm) are significantly larger than males (34–40 cm), and spawning females are larger than non- spawning females.

The common percarina is distinguished from its congener P. maeotica by having no scales on its cheek, by having nearly transparent membranes on the body and fins, the upper body is milky white in colour with no spots. It also has 8-9 round or irregular markings on the base of both dorsal fins. The dorsal fins are clearly separate in both species of Percarina and in this species the first dorsal fin contains 9-10 spines while the second dorsal fin contains 3 spines and 10-12 soft rays. The anal fin has 2 spines and 8-11 soft rays.

Right whale dolphins lack dorsal fins. Shown is the northern species, so the only white parts are the bellies, hidden from this angle. Both species are highly gregarious. They move in pods of several hundred individuals and sometimes congregate in groups of 3000.

Schilbid catfishes usually have dorsal fins with a short base and a spine, but Parailia lack a dorsal fin altogether. Most species also possess an adipose fin. The base of the anal fin is very long. There are usually four pairs of barbels.

Dorsal fins with convex posterior margins. Color pattern of purple and pink spots, with dark bands and a white body. The coloration is unique in this family making it very simple for identification. The teeth of bamboo sharks are not strongly differentiated.

They have 10 dorsal fins and 12 anal fins. Adult males have long filaments on their tail fin lobes and prolonged rays posteriorly on the dorsal and anal fins. They have 17 pectoral rays. The lateral line is unbroken and smoothly arched.

This species grows to a length of TL. it has an elongate body with long anal and dorsal fins. It has small, chisel-like teeth that are useful for consuming algae from tough surface. It ranges in color from yellowish to green brown.

In comparison, the southern sleeper shark differs from S. microcephalushas in having more tooth rows in the lower jaw, a shorter interdorsal region, a more posterior first dorsal fin, and fewer precaudal vertebrae, and from both species in having lower dorsal fins.

The pectoral fin has a shallowly concave posterior margin. The first dorsal fin is moderately high, and both dorsal fin spines are very stout. Coloration is light grey above, paler below, with no white spots. The pale dorsal fins have dusky tips.

Juvenile houndfish possess an elevated, black lobe on the posterior of their dorsal fins. The longest recorded houndfish was ,Sommer, C., W. Schneider and J.-M. Poutiers 1996 FAO species identification field guide for fishery purposes. The living marine resources of Somalia.

The silver hake is a long, thin species with a protruding lower jaw and two dorsal fins. This hake is named as such for its silvery coloring, while darker dorsally. They typically grow to be about , but can reach a maximum length of .

Cladoselachidae is an extinct family of cartilaginous fishes and among the earliest predecessors of modern sharks. They are the only members of the order Cladoselachiformes and were characterized by having an elongated body with a spine in each of the two dorsal fins.

The orange-spotted snakehead (Channa aurantimaculata) is a species of snakehead fish. Its body is of brownish colour intermixed with vertical orange stripes. Males have taller dorsal fins with more intense coloration, and narrower heads. It is endemic to Brahmaputra River basin.

This species is light grey or bronze above, often with small white spots on the sides, and pale below. The dorsal fins are tipped in white, which is especially obvious on the second dorsal as the remainder of fin is mostly dark.

Sawsharks have a pair of long barbels about halfway along the snout. They have two dorsal fins, but lack anal fins. Genus Pliotrema has six gill slits, and Pristiophorus the more usual five. The teeth of the saw typically alternate between large and small.

Fish of this family have dorsal fins covered by skin. An adipose fin is also present, and is fused with the caudal fin in some species. The dorsal fin base is short and the dorsal fin spine is weak. The anal fin base is short.

The head and upper flanks are dark with a silver tinge paler on the lower flanks. It has a semi transparent snout. Both dorsal fins and the caudal fin are translucent with a sooty rear margin. The anla fin is blackish with a whitish tip.

The Blue blanquillo is the only species within the genus Malacanthus, which itself is in the family Malacanthidae, commonly known as tilefish. The Malacanthidae are part of the Percoidea, a suborder of the order Perciformes. Both subfamilies have relatively long dorsal fins and anal fins.

The kidney of the perch runs along the backbone and forms a head, caudal to the gills. Perch have paired pectoral and pelvic fins, and two dorsal fins, the first one spiny and the second soft. These two fins can be separate or joined.

The pectoral fins are placed low on the sides. Its swim bladder is large. Speedy and dynamic, they are slim, with small scales. Barracudas also have two well-separated dorsal fins, a protruding lower jaw, and a large mouth with many large, sharp teeth.

This species is light grayish brown on the back of the body and tail, with a series of dark brown saddles numbering 10–16 before the dorsal fins, of which a few are wider than the others. The flanks, underside, and fins are whitish.

Zingel zingel is distinguished has two separate dorsal fins with 13-15 spines in the first dorsal fin and 18-20 soft rays in the second dorsal fin. There are no scales on the cheeks. They grow to in length with a maximum length of .

Members of this species reach 3.2 cm (1.3 in) total length, and have 27 vertebra.Palatogobius grandoculus Greenfield, 2002 FishBase. Their dorsal fins contain only 8 spines but 17–18 soft rays. Similarly, their anal fins have only one spine, but 18–19 soft rays.

The Azov percarina is distinguished from the closely related common percarina, Percarina demidoffii, by its unique characteristics of having scaled cheeks, pigmented body back and grey flanks with numerous small dark dots, which may be fused into larger spots along base of the dorsal fins.

In male specimens, particularly alpha males, the border is conspicuously wider, and in breeding alpha males, can cover up to a third of the total area of the anal fin. This is the only reliable means of differentiating gender in this species - while males frequently have taller and more pointed dorsal fins, some females also possess tall, pointed dorsal fins, and thus this characteristic is not reliable. Ripe females are fuller bodied, particularly when viewed from directly above, as the body cavity expands to accommodate the eggs forming within the female's reproductive tract. Juvenile fishes are usually translucent with only a hint of the colour of the adult.

Western carp gudgeon are small fish, averaging 30–40 mm long, though very large specimens may approach 60 mm. Usually, their bodies are yellowish to clear with subtle, dark grey blotches, with semitranslucent fins. Males develop spectacular spawning colours in summer, namely a more metallic-bronze body colour with a red stripe through the caudal (tail), anal, and spiny and soft dorsal fins. The red stripe through the anal and spiny and soft dorsal fins are topped with a tiny iridescent blue-white stripe, which are somewhat subtle on most of the fins, but are prominent and eye-catching on the spiny dorsal fin.

Many fish swim using combined behavior of their two pectoral fins or both their anal and dorsal fins. Different types of Median paired fin propulsion can be achieved by preferentially using one fin pair over the other, and include rajiform, diodontiform, amiiform, gymnotiform and balistiform modes.

The scales are relatively large and longer vertically than horizontally. The eye is large and has a blue iris. There are two dorsal fins, the first arising in line with or just posterior to the longest pectoral fin ray. The forked tail fin has rounded tips.

Its two moderately large dorsal fins are roughly equal in size. It is brownish gray above and lighter below, with a pattern of darker saddles and blotches in younger sharks. This species reaches in length. The diet of the whiskery shark consists almost entirely of octopuses.

The stone bream is often blue and silver in color. Each stone bream has anywhere from 6-8 dorsal fins and 20-25 dorsal soft rays. They are also equipped with 3 anal spines and around 20-26 anal soft rays. They have very small mouths.

Male guppies, which are smaller than females, have ornamental caudal and dorsal fins. Wild guppies generally feed on a variety of food sources, including benthic algae and aquatic insect larvae. Guppies are used as a model organism in the fields of ecology, evolution, and behavioural studies.

Southern sennet have six spines, and 9 rays on their dorsal fins. they have only two spines and 9 rays on their anal fins. The longest recorded southern sennet was 2 ft long;IGFA 2001 Database of IGFA angling records until 2001. IGFA, Fort Lauderdale, USA.

In: Froese, R. and D. Pauly, Editors. FishBase. Accessed through: World Register of Marine Species. These fish have protrusible, toothless or nearly toothless jaws, long dorsal fins, and forked tail fins with lobes that fold in like scissors. The largest species reach about 50 centimeters in length.

The adult rock beauty is mostly yellow, turning blue toward the tail. The tail itself is yellow. The pectoral fins and ventral fins are yellow, and the lips and the edges of their dorsal fins and anal fins are dark blue. The adult measures up to .

Its head is short, representing between 21% and 24% of the shark's total length. The front of its snout is blunt and round. It has two high, narrow dorsal fins and a low, broad anal fin. The pectoral and pelvic fins have a somewhat triangular shape.

Identification of this species is very easy due to the pattern of harness-like markings that cross the eyes, run along the back to the first dorsal fin, then cross the side of the body, in addition to the spine in front of both dorsal fins.

Both sexes have 24 vertebrae, of which 11 are precaudal and 13 are caudal. . The marlin has two dorsal fins and two anal fins. The fins are supported by bony spines known as rays. Its first dorsal fin has 39 to 43 rays from front to back.

They also have relatively larger dorsal fins. The adults have a white spine on the caudal peduncle. The large, sail-like dorsal fin has 4 or 5 spines and 23 to 25 soft rays. The anal fin has 3 spines and 19 to 21 soft rays.

Gamera grabs another boulder and uses it, like a mallet used to play a xylophone, to play the Gamera theme on Zigra's dorsal fins. Finally, Gamera kills Zigra by setting its body on fire with his flame breath, reducing it to ashes in a massive conflagration.

The front of the first of two dorsal fins is the location of its one spine. The one anal fin is made up of a total of 123-125 soft rays. They possess paired pectoral and pelvic fins. The pectoral fins have 14-17 soft rays.

In addition to the breeding male's changes, other sexual dimorphic characters include slightly larger paired, anal, and dorsal fins in the female, and faster growth rate and larger size in the male. For example, a typical four-year-old male is about 18 cm and female about 13 cm.

Their dorsal fins are very long, and the fish flicks it back and forth. This is used as a signal to conspecifics. As a full grown adult, it reaches a maximum length of . Adults occupy sandy burrows alone or in pairs, while the juveniles live in small groups.

Adults usually can be found in pairs, while juveniles are solitary. When threatened, these fishes display their large ventral and dorsal fins. They feed primarily on filamentous algae, various macroalgae and plankton. However, individuals were regularly observed feeding on jellyfish (Scyphozoa) and comb jellies (Ctenophora) in the Red Sea.

The spotfin lionfishFroese, Rainer, and Daniel Pauly, eds. (2012). Species of Pterois in FishBase. December 2012 version. or broadbarred firefish (Pterois antennata) is a fish found in the tropical Indian and Western Pacific Oceans; it grows to a maximum of and, like other lionfish, has venomous spiny dorsal fins.

There are two dorsal fins on this gray-blue fish: the first consists of about six stiffly held rays (often with a black blotch); the second is equal in length to the long-based anal fin. Both carry dark spots. This species can reach a length of SL.

The Sargassum blenny has two quite distinct dorsal fins. The face is elongated and the mouth resembles that of a pike. There are no cirri. The general colour is brown with patches of silver on the flanks and there are 2 blue eyespots on the posterior dorsal fin.

It has a semi- translucent snout. The first and second dorsal fins are coloured dusky yellow; the pectoral fin is black while the pectoral filaments are translucent. The dusk yellow anal fin has a white rear margin. The caudal fin is dusky yellowish with a black rear margin.

Trichonotus species have jutting lower jaws, five soft rays, and single pelvic spines. In males, the anterior rays on their dorsal fins may be extended. Their lateral lines run along the middle flank. On the back end of the lateral line scales is a deep, V-shaped notch.

Another ancestral quality of the Squalodontidae is their necks. Squalodontid necks are more compressed than their ancestors, the Archaeoceti. Compared to toothed whales at that time, the squalodontids were likely more mobile. Paleontologists also believe that the dorsal fins were reduced but larger than that of the ancestors.

Their bodies are elongated and fusiform, with spinous and soft dorsal fins widely separated. Their tail fins are large and deeply forked; indicating speed and agility. The mouth is large and inferior; a blunt snout projects far ahead. The jaws and palate possess bands of villiform (fibrous) teeth.

Snout moderately long and bluntly rounded viewed from the side. Fins have fleshy bases although the paired fins less so. Fins rounded, anal and dorsal fins roughly the same length with the dorsal usually slightly longer. Pelvic fins positioned approximately mid way along the body, pectoral fins paddle shaped.

The Aulopidae are a small family of aulopiform fish. They are found in most tropical and subtropical oceans, and are commonly known as flagfins. The aulopids resemble lizardfishes in appearance, and range up to in length. They have large dorsal fins, the first ray of which is greatly extended.

Additionally, the western wobbegong does not have any warty tubercles (wart-like growths) on their backs, and has relatively larger dorsal fins. O. hutchinsi has four equally spaced gills on the side of its head which it uses to filter oxygen from the surrounding water in order to breathe. The fins of the western wobbegong are the pectoral fins, a triangular pelvic fin, a lobe-like anal fin, a caudal fin, and triangular dorsal fins. Their eyes are located on their heads, and O. hutchinsi’s eyes have a duplex retina. Having a duplex retina means that the western wobbegong shark’s eyes contain both rods and cones, for light sensitivity and color resolution, respectively.

Collapsed or collapsing dorsal fins are rare in most wild populations and usually result from a serious injury to the fin, such as from being shot or colliding with a vessel. After exposure to the 1989 Exxon Valdez oil spill, two male resident killer whales experienced dorsal fin collapse, and the animals subsequently died. In 2002, the dorsal fin of a stranded killer whale showed signs of collapse after three days but regained its natural upright appearance as soon as the orca resumed strong normal swimming upon release. A study in 1998 recorded that 7 out of 30 (23%) adult male killer whales off the coast of New Zealand had abnormal dorsal fins.

Tomiyamichthys alleni has meristic counts of 6-7 spines and 10 soft rays in the dorsal fins and a single spine and 10 soft rays in the anal fin. It is pale grey on the back with 4-5 irregular brown saddle-like blotches running from the nape to the caudal peduncle and the ventral side is white. There is a scattering of orange spots with darke margins on the head and body and there is an oblique black band under each eye. The first and second dorsal fins are marked with orange spots orange spots and there are 2-3 dark spots close to the margin of the first dorsal fin.

The Potomac sculpin has a large head and mouth, with the eyes located on the upper part of the head. It has fan-like pectoral fins, and connected dorsal fins. It has twenty-six or fewer lateral-lines pores. In addition, it has four pelvic fins and fifteen pectoral fins.

Ocean surgeons have a total of 9 spines on their Dorsal fins and between 23 and 26 soft rays. Their anal fins have only 3 spines and between 21 and 23 rays. Their caudal fins are roughly emarginate, and the surgeonfish's body and head are both deep and compressed.Randall, J.E. (1996).

Retrieved on October 17, 2009. The five pairs of gill slits are short and nearly vertical. The body of the Portuguese dogfish is thick and cylindrical except for the flattened belly. The two dorsal fins are small and of similar size and shape, each bearing a tiny grooved spine in front.

They have red eyes and the dorsal fins are edged with cream or gold. The body is encased in heavy armour, except for the belly, which is soft. This armour is made of strong plates of skin, not scales. Royal panaques can grow to 43 centimetres (17 in) in length.

89 pp. They can be identified from other common minnow species by the black "moustache" on their upper lips, along with a black dot on their dorsal fins. Additionally, juvenile males develop a rosy band on their sides, along with glossy, dark dorsal fin spots.Etnier, D.A., and W.C. Starnes. 1993.

Both have straight leading margins and somewhat angular apexes. The space between the dorsal fins is greater than the space between the second dorsal and caudal fins. The caudal peduncle is flattened and expanded laterally to form keels. The lower lobe of the caudal fin is markedly larger than the upper.

This lamprey is usually about long, but specimens have been known to reach and in weight. Non-anadromous individuals are rarely over long. It is brown, gray, or olive in color with a paler belly. There are two dorsal fins located near the tail, the posterior one larger than the anterior.

The combtooth dogfish has no anal fin, grooved dorsal spines, two dorsal fins of about same size, a pointed nose, large eyes, small gill slits, a short abdomen, a short caudal peduncle, and is blackish-brown in color with white-tipped fins. It grows to a maximum of 50 cm.

The males guard harems of several females and when courting their colour intensifies and they erect their red dorsal fins. ike all species of Pseudanthias they are nonandric protogynous hermaphrodites in which all the fish are born female and the largest and most dominant females will change sex to become males.

Eustomias schmidti has an elongated and slender body. The head is quite small with large jaws that are about the same length as the head. The jawbone has small, erect teeth standing in an anterior direction. Each Eustomias schmidti has 22–28 dorsal fins and 36–43 anal soft rays.

Australian rainbowfish reach maximum lengths of , but the males are usually no larger than , while the females usually only grow to . The body is elongated, with a small head and large eyes. Australian rainbowfish have two dorsal fins and a pointed anal fin. The caudal (tail) fin is forked shallowly.

The Yaqui sucker's body is fusiform and somewhat elongated, with relatively large head and eyes. The lips can be distinguished in that they are less fleshy than other Arizona suckers. The high dorsal fin has twelve fin rays. Anal, pelvic, and dorsal fins are all particularly larger in males than females.

The first dorsal fin is positioned closer to the pelvic than the pectoral fins, which are very short and broad. The second dorsal fin is much smaller than the anal fin. No ridge occurs between the dorsal fins. The back is bronze-gray in color, and the belly is white.

No ridge is seen between the dorsal fins. The pectoral fins are long and broad, originating below the space between the third and fourth gill slits. The anal fin has a strong notch in the rear margin. The precaudal pit (a cavity just forward of the caudal fin) is oriented longitudinally.

They had flippers instead of legs, and except for early species, had dorsal fins. Although no evidence is specific to Acamptonectes, at least some ichthyosaurs may have been uniformly dark-colored in life, demonstrated by the discovery of high eumelanin contents in the preserved skin of an older ichthyosaur fossil.

The dermal denticles are tiny, smooth, and non-overlapping. Adults are grayish to golden brown above and white below, with faint darker saddles and white patches on the dorsal fins. Juveniles have a striking pattern of large black markings on a white background. This species can grow up to long.

Graveldivers are small fish, reaching lengths of only , but usually not exceeding . They are long and compressed, resembling blennies. The head is snake-like, and the dorsal fins and anal fins have no soft rays, and are supported only by thin spines. Each has 41–51 spines, originating deep in the skin.

They typically grow up to TL in length. Like their name implies, they are typically solid red with males of the species being more intensely colored, but a few rarely have green side. Males have more-so pointed dorsal fins and longer pelvic fins. Females are generally rounder and have an egg tube.

The species measured SL in length. The body shows typical halfbeak shape with an elongated lower jaw and cylindrical elongated body. They have no spines on fins, but do have 11-12 rays of their dorsal fins and 12-13 rays on their anal fins. Pectoral fin is much shorter than head length.

The Muraenesocidae, or pike congers, are a small family of marine eels found worldwide in tropical and subtropical seas. Some species are known to enter brackish water. Pike congers have cylindrical bodies, scaleless skin, narrow heads with large eyes, and strong teeth. Their dorsal fins start above the well-developed pectoral fins.

The boga's life colors are generally greenish above, and blueish-white below. A greenish stripe, tinged with yellow, can be seen from the eye to the tail. Three similar stripes are on the back. The snout and dorsal fins are both yellowish or pale yellow, while the caudal fin is dusky violet.

The maximum reported length for this ray is 64 cm. It has a rounded pectoral fin disc and two dorsal fins, with the base of the first placed entirely above the pelvic fins. The tail has a ridge-like lateral fold and a small caudal fin. The spiracles are fringed with small papillae.

The pectoral fin has a shallowly concave posterior margin. The first dorsal fin is moderately high with a short spine.Compagno, Dando, & Fowler, Sharks of the World, Princeton University Press, New Jersey 2005 Coloration is light grey above, paler below, with no white spots. The pale dorsal fins have dusky tips and posterior margins.

The teeth are mostly exposed when the mouth is closed. The tail is equal in length to the disk, with loose lateral folds of skin and two dorsal fins of equal size. The tips of the dorsal and caudal fins are angular. The skin is soft and loose, without denticles or thorns.

A series of several large black dots then run horizontally along the lateral line area. The fins are often a dark to black colouration, especially when in spawning colouration. The female is similarly colored, but generally smaller than the male. The female will also lack the elongated extensions to the dorsal fins.

Brown catsharks have long, slender bodies with broad, bell-shaped snouts. They are dark brown with light-colored markings on the posterior margins of their fins. Their bodies are soft and flabby, with a weak skin that can easily be harmed. Brown catsharks' two dorsal fins are the same size and do not have spines.

The Malapteruridae are the only group of catfish with well-developed electrogenic organs; however, electroreceptive systems are widespread in catfishes. The electrogenic organ is derived from anterior body musculature and lines the body cavity. Electric catfish do not have dorsal fins or fin spines. They have three pairs of barbels (the nasal pair is absent).

A spiracle is present, but small. The dorsal ends of the fourth and fifth branchial arches are attached, but not fused into a "pickaxe" as in lamniform sharks. Heterodontiforms have two dorsal fins, with fin spines, as well as an anal fin. The dorsal and anal fins also contain basal cartilages, not just fin rays.

The pectoral fins are distinctively large and triangular, with rounded to pointed tips. The large first dorsal fin originates over the rear of the pectoral fin bases. The second dorsal fin is relatively tall and long, and originates over or slightly behind the anal fin origin. There is no ridge between the dorsal fins.

Their bodies are compressed, giving them a triangular cross-section. They have two large dorsal fins, each with a sharp spine, and with the first fin placed far forward above the head. Even more so than their relatives, the dogfishes, they have rough and prickly skin. Unusually among sharks, they also possess a luminous organ.

Their coloration is fairly uniform and can range from brown to grey. Arnoux's beaked whales are around four meters as calves and can reach lengths up to 9.75 meters as adults. Their bodies are not as narrow as the Baird's, and resemble a spindle. Unlike the Baird's beaked whale, Arnoux's have slightly hooked dorsal fins.

Bostrychus expatria is a small fish reaching a length of . They appear as standard members of their family, with non-hydrodynamically- shaped bodies typical of bottom-dwelling fish. It possesses two completely separate dorsal fins, the first one supported by spines. The caudal fin is truncately-shaped, usually not much thicker than the peduncle itself.

Head of a European sea sturgeon The wedge-shaped head of the European sea sturgeon ends in a long point. There are many sensitive barbels on the facial area. The dorsal fins are located very far back on the body. Five longitudinal lines of large osseous plates are found on the body of the fish.

The smoothback angelshark can reach a length of up to 1.6 metres. As with other angelsharks, its body is flattened by very wide pectoral fins, giving it the appearance of a long ray. Unlike in rays, however, the pectoral fins are clearly separated from the body. They have two dorsal fins and no anal fin.

Gymnothorax pseudothyrsoideus can grow to 80 cm in length and has no visible dorsal fins. Its coloration is pale yellow with dark brown spots that are irregularly distributed across its body. The young have white along the margins of their fins, but as they mature the white fades to only the tip of the tail.

Ischanacanthiformes is an order of Acanthodii or spiny sharks found in Canada, Ukraine and United Kingdom. Members of this order were nektonic carnivores, eating animals that swim rather than plankton. They had slender builds, light armor, deeply inserted spines, shark-like teeth, and two dorsal fins. Some species were around 2 meters (6.56 feet) long.

The body is strongly compressed laterally. The dorsal fins are situated approximately in the middle of the body. The first dorsal fin (with five to six rays) is arched and originates from the highest point of the back of the fish. It has thinner rays than the second dorsal fin (with seven to eight rays).

The alligator pipefish is an inefficient swimmer, moving by an undulating motion of its pectoral and dorsal fins. It feeds on zooplankton and small creatures which it sucks into its mouth. The diet includes amphipods, mysids, shrimps, other benthic invertebrates and small fish. The alligator pipefish is sexually dimorphic with males being larger than females.

Because of its long body and sharp teeth, the California lizardfish is occasionally mistaken for the barracuda. The barracuda, however, is silvery rather than brown and has two similar-sized dorsal fins with a wide space between them, whereas the lizardfish only has a single dorsal fin with a tiny fleshy fin behind it.

The mandibular barbels have long, slender branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. xiphias, the spine is smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

An adult lake lamprey is dark blue or dark brown with a lighter belly, and the body is 11.8-27.3 cm in length. The lamprey's disc-like mouth is filled with sharp teeth. The Vancouver lamprey has eyes on the top of its head, two dorsal fins, a caudal fin, and an anal fin.

The fish that lives in a sea cucumber anus, Australian Geographic, 8 August 2014 Regardless of the habits of the adults, the larvae of pearlfish are free-living among the plankton. Pearlfish larvae can be distinguished by the presence of a long filament in front of their dorsal fins, sometimes with various appendages attached.

Dorsal fin diagram with landmarks labeled. Most sharks have eight fins: a pair of pectoral fins, a pair of pelvic fins, two dorsal fins, an anal fin, and a caudal fin. The members of the order Hexanchiformes have only a single dorsal fin. The anal fin is absent in the orders Squaliformes, Squatiniformes, and Pristiophoriformes.

The ornate wobbegong's upperside is golden brown in colour with blueish-grey areas, and it is yellow-green on its underside. It has two dorsal fins, a large flat head, and small eyes. Its mouth and lower head are covered with flaps of skin. Juveniles are in total length and sexual maturity is reached at .

The ppper sides of head and the flanks are tinged golden silver, becoming silvery on the lower flanks. Both dorsal fins are pale brown, the pectoral and pelvic fins are vivid yellow. The front portion of the anal fin is yellow, the remainder being yellowish white. The pectoral filaments are white or yellowish white.

Belted cardinalfish reach a maximum length of . They have two dorsal fins; there are six spines in the first and one on the first with nine rays. The pectoral fins have 12 rays and the anal fins have two spines and eight rays. The caudal (tail) fin is forked with twelve scales around the caudal peduncle.

There are five pairs of short gill slits. The pelvic fins are only slightly overlapped by the disc; each is long, wide, and roughly triangular, with trailing margins that are more concave in males than in females. The tail is stout and much shorter than the disc. Unique amongst electric rays, there are no dorsal fins.

The second dorsal fin is less than a third as high as the first, and originates ahead of the anal fin. There is no midline ridge between the dorsal fins. The long pectoral fins are broad and slightly falcate (sickle-shaped), becoming narrow and pointed at the tips. The anal fin has a sharply notched trailing margin.

The eyes and spiracles are large. The mouth is broadly arched, containing many teeth with narrow cusps and lateral cusplets. There are two roughly equal-sized dorsal fins with grooved spines; the second spine is longer than the first and slightly curved. The pectoral fins are short and broad, not reaching the first dorsal fin base when folded back.

The anal fin is absent. There is a strong ridge running between the pectoral and pelvic fins on each side of the body. The dermal denticles are large and widely spaced, giving the skin a very rough texture. This species differs from the similar sailfin roughshark in the positioning of the dorsal fins and the shape of the spiracle.

On the west coast of Alaska and the Aleutian Islands, seal and sea lion populations have also substantially declined. alt=Two killer whales, one large and one small, swim close together. Their dorsal fins curve backward. In 2005, the United States government listed the southern resident community as an endangered population under the Endangered Species Act.

The pectoral fins of adults are broad and falcate (sickle-shaped). The dorsal fins have nearly vertical trailing margins, with the first originating over the pectoral fin rear tips. The second dorsal fin is about three-quarters as high as the first. The anal fin is much smaller than the second dorsal fin and originates well behind it.

Most of its fins (dorsal, pectoral, pelvic and caudal) have white tips (juvenile specimens and some adults may lack these). Along with white tips, the fins may be mottled, and young specimens can have black marks. A saddle-like marking may be apparent between first and second dorsal fins. The shark has several kinds of teeth.

The maxilla does not extend below the anterior margin of the eye. The teeth are conical and are present in double rows on both jaws. The eyes are directed slightly upwards and sideways. The dorsal fins are close together, with the first dorsal fin having five to seven rays and the second having 12 to 15.

Adults Roanoke logperches are between 80 and 115 mm SL. The light-colored body is somewhat stocky and elongated. There are dark, rounded, and vertically elongated blotches on the side. The fish have a long, cone-shaped snout with a bulbous or blunt tip. There are two dorsal fins, which are both very tall on adult males.

The long and narrow pectoral fins are falcate (sickle-shaped) with pointed tips. The large first dorsal fin is also falcate and originates over or slightly behind the rear of the pectoral fin bases. The second dorsal fin is moderately tall and positioned about opposite the anal fin. There is no midline ridge between the dorsal fins.

There is a single nostril near the eyes. There are no gill covers and the seven gill openings are visible just behind the head. The fish has no scales or paired fins, but has two elongated dorsal fins, the hindmost of which nearly joins onto the small tail fin. The Caspian lamprey is a silvery-grey colour.

Southern sennet, like other members of the family Sphyraenidae, possess elongated bodies, pike-like heads, and large jaws. The lower jaw protrudes slightly from the upper jaw, both of which contain fang- like teeth. They have two dorsal fins, which are widely separated on their backs. The anterior dorsal fin usually possesses spines, while the posterior only has rays.

Australian bass have a moderately deep, elongated body that is laterally compressed. They have a forked caudal ("tail") fin and angular anal and soft dorsal fins. Their spiny dorsal fin is relatively high, strong and sharp. They have a medium-sized mouth and relatively large eyes than can appear dark in low light or red in bright light.

This species grows to an average length of and a weight of . Compared to other members of the Salvelinus genus, it has a deeper body that is more laterally compressed, a shorter caudal peduncle and larger scales. It can be distinguished from other char by the whitish spots on upper flank and caudal and dorsal fins.

The comber has a relatively stout body with a large head and a prominent jaw. It has two dorsal fins, the first has 11 thin spines and is joined to the second, which has 13-15 branched rays. The anal fin has 3 spines and 7-8 soft rays. The caudal fin is slightly truncate in shape.

It has a deeply forked tail and is blue-greenish silver with yellow on the throat, belly, and pelvic and anal fins. The first dorsal fins are low, with about six separate spines. The first spine may be reabsorbed in a larger fish. The second lobes on the dorsal and anal fins have a lower anterior.

The story may have arisen from mariners mistaking the tall dorsal fins of killer whales, which do attack large cetaceans, for thresher shark tails. Swordfish bills have also been found embedded in blue and fin whales (likely accidents due to the fast- moving fish's inertia), and thresher sharks do exhibit some of the aforementioned behaviors independent of whales.

Its teeth were multi-cusped and smooth-edged, making them suitable for grasping, but not tearing or chewing. Cladoselache therefore probably seized prey by the tail and swallowed it whole. Its sturdy but light-weight fin spines were composed of dentine and enamel. Cladoselache also had a blade-like structure which was positioned in front of the dorsal fins.

The heaviest was recorded to weigh . Western Atlantic seabream have nine spines on their dorsal fins, and 10–11 soft rays. On their anal fins, they have only three spines, but the same number of rays. The large intestine of the Western Atlantic seabream makes up roughly 90% of the length of its entire digestive tract.

They also possess two dorsal fins with separate bases, as opposed to the single dorsal fin of ray-finned fish. The braincase of lobe-finned fishes primitively has a hinge line, but this is lost in tetrapods and lungfish. Many early lobe-finned fishes have a symmetrical tail. All lobe-finned fishes possess teeth covered with true enamel.

It had large eyes, suggesting that it hunted by sight. It was a small fish, at , and to discourage predators, Climatius sported fifteen sharp spines. There was one spine each on the paired pelvic and pectoral fins, and on the aingle anal and two dorsal fins, and a four pairs without fins on the fish's underside.

Gurgesiella atlantica, commonly known as the Atlantic pygmy skate, Atlantic finless skate, or simply the Atlantic skate, is a skate species in the family Gurgesiellidae. It lives in the western central and southwest Atlantic Ocean, from Nicaragua to Brazil. It grows to – long and is distinguished from other skates by its long, slender tail and absence of dorsal fins.

The pelvic fins are completely separated, no membrane is present between the first and the second dorsal fins. The first dorsal fin is shallow and its margin rounded, and the fourth spine is slightly longer than the other spines. The caudal fin in adults is deeply notched with two long filaments. Juveniles have more rounded caudal fins.

The tail measures less than an eighth as long as the disc and is moderately flattened at the base, tapering smoothly to a lance-shaped caudal fin. There are no dorsal fins or fin folds. A single, serrated stinging spine is placed atop the tail, well behind the base. The skin is devoid of dermal denticles.

The Iniidae have adapted morphology common to freshwater riverine habitats. These adaptions include cervical vertebra that are not fused, allowing for a flexible neck. Also, their dorsal fins are highly reduced or absent so they do not become entangled in vegetation from the flooded terrestrial plains. Large, wide, paddle-like pectoral fins allow for maneuverability in small vegetated areas.

C. parasema is blue with a distinctive yellow caudal fin (tail fin). The yellow coloring may extend up to the back of the anal and dorsal fins, especially in species from Papua New Guinea. These fish may also have yellow pelvic or pectoral fins. However, yellow is never found on the backs or bellies of Yellowtail Blue damsels.

Most hyperoliids lay their eggs in water, although foam nesting, tree-hole breeding, and laying of eggs in vegetation above water are all known behaviors. Afrixalus builds leaf nests for its eggs, by folding and gluing the edges of the leaves. Tadpoles are pond type larvae with large dorsal fins on their tails. No fossil hyperoliids are known.

Ecotype D represents a group of killer whales that have been discovered in the 1950s in New Zealand, but only have rarely been seen since. They have black and white coloring along with a saddle patch, but they have shorter dorsal fins, a rounder head, and the smallest eye patch of any of the other ecotypes known.

This is generally not very successful, and should not be attempted, as purebred Yucatan mollies are often quite hard to find, and hybrids will not have as massive dorsal fins as these. Several color variants are also available; these usually do not attain the large size of wild-type fish and may have been crossbred with P. latipinna.

Shonisaurus was also traditionally depicted with a dorsal fin, a feature found in more advanced ichthyosaurs. However, other shastasaurids likely lacked dorsal fins, and there is no evidence to support the presence of such a fin in Shonisaurus. The upper fluke of the tail was probably also much less developed than flukes found in later species.Wallace, D.R. (2008).

Mouth is protractible, upwardly directed, with small teeth. Lower jaw has an upper expansion within mouth (high dentary bone). There are two separate dorsal fins, with all rays of first and 1-2 anterior rays of second dorsal fin being unsegmented. The anal fin is similar to the second dorsal fin, while the caudal fin is forked.

Gavin Maxwell, who fished for basking sharks nearby in 1947, recorded a mass sighting of these sharks; quoted in “It was a gigantic shoal ... At one moment we counted 54 dorsal fins in sight at the same time.” The island has nesting sites for Arctic and common tern, kittiwakes and eider ducks and also has a large seal colony.

N. depressifrons is a small species, reaching a maximum size of 10 cm. It is similar to the bullrout in shape and colouration - mottled brown with a distinctive light stripe running along the dorsal surface from the nose and along the back of the fish. It has two dorsal fins, the first being notably taller than the second.

Guachanche barracuda, like other members of the family Sphyraenidae, possess elongated bodies, pike-like heads, and large jaws. The lower jaw protrudes slightly from the upper jaw, both of which contain fang- like teeth. They have two dorsal fins, which are widely separated on their backs. The anterior dorsal fin usually possesses spines, while the posterior only has rays.

Sonora suckers have a fusiform body, with large heads and chubby figures. They have generally large lower lips, with no fleshy lobes. Sonora suckers have unique square dorsal fins, and relatively large scales (but fewer than most fish in the genus Catostomus). Their coloration is distinctly bi-colored, with a yellow underside and brownish dorsal side.

Mirrorwing flyingfish have 10-12 soft rays on their dorsal fins and 11-13 rays on their anal fins. Their bodies are generally dark, with blue on top and silver-white on bottom. The dorsal and caudal fins are both grayish, while the other fins are hyaline.Heemstra, P.C. and N.V. Parin 1986 Exocoetidae. p. 391-396.

Two dorsal fins occur with the base of the first placed well forward of the pelvic fins. The caudal fin has a strong ventral lobe and undulations on the dorsal lobe margin. They feed on a variety of small bony fishes and invertebrates; at least two species specialize on cephalopods. They are not known to have attacked people.

Teeth small, bluntly conical, and arranged in numerous series. Slender branchiostegal rays not curving round the opercular apparatus. Vertebrae exceeding 100 in number, the hindermost bearing a pair of expanded hypural bones. Pectoral fins present; dorsal fins arising immediately behind the occiput and extending to the caudal fin, which has stouter rays and is very small but separate.

They have large pectoral and anal fins, and two similar dorsal fins placed well back. Many species are ornately patterned with dark saddles and/or blotches. Sawtail catsharks feed on various invertebrates and fishes, and may be either egg- laying or live-bearing. These harmless sharks are sometimes caught as bycatch but are of minimal commercial value.

The green terror (Andinoacara rivulatus, syn. Aequidens rivulatus), is a colorful freshwater fish in the cichlid family. The fish originates from the Pacific side of South America from the Tumbes River in Peru to the Esmeraldas River in Ecuador. It is polymorphic and can have white or gold-orange edging to the tail and dorsal fins.

Reconstruction Bothriolepis had a long pair of spine-like pectoral fins, jointed at the base, and again a little more than halfway along. These spike-like fins were probably used to lift the body clear off the bottom; its heavy armor would have made it sink quickly as soon as it lost forward momentum. It may also have used its pectoral fins to throw sediment (mud, sand or otherwise) over itself. In addition to the pectoral fins, it also had two dorsal fins: a low, elongated anterior dorsal fin and a high rounded posterior dorsal fin —though the hypothesized structure of the dorsal fins varies based on the specific species of Bothriolepis and has been modified several times in the reconstructions released by researchers as new information has become available.

The scales on the body cannot form a chevron pattern. The skin ridge running the length of the sides of the body, spread as far as one-third of the base of the anal fin. Low and long set dorsal fins consist of 52 to 61 rays. The anal fin is about half the size of the dorsal fin, and taller.

The body shows typical halfbeak shape with an elongated lower jaw and cylindrical elongated body. They have no spines on fins, but do have 13-16 rays of their dorsal fins and 13-16 rays on their anal fins. The longest recorded Jumping halfbeak was 35 cm long, but most of them are 13 cm long commonly. Caudal fin emarginate.

Shastasaurus was also traditionally depicted with a dorsal fin, a feature found in more advanced ichthyosaurs. However, other shastasaurids likely lacked dorsal fins, and there is no evidence to support the presence of such a fin in any species. The upper fluke of the tail was probably also much less developed than the shark-like tails found in later species.Wallace, D.R. (2008).

Their common and species name comes from them having dorsal fins of very different sizes, shapes, and areas compared to other angel sharks. Disparate angelsharks are usually dark brown on top (dorsal surface) without any thorns or eyespots (ocelli) though they do have two distinct round black spots on the upper edge of their pectoral fins and irregular, scattered whitish spots.

Pompano dolphinfish have compressed heads and dorsal fins extending the entire length of their bodies. Mature males develop a protruding forehead, but not to the same extent as male mahi-mahi. Their backs are a brilliant blue-green, and their sides are a silvery-golden color. When they are removed from the water, the fish fade to a muted green-grey upon death.

Atherina hepsetusThe body is rather long, slender and moderately flattened. The mouth is protrusible, directed upward with small teeth; the head and body are scaly. The lower jaw has an upper expansion within the mouth (high dentary bone). Two separate dorsal fins, all rays of first and 1-2 anterior rays of second dorsal fin are unsegmented, with the remaining rays segmented.

Diamond darters have 11-13 spines on their dorsal fins, and 11-15 soft rays. However, their anal fins do not have any spines at all, and only 11-13 soft rays. Adults are estimated to be 3-5 in long, with the largest specimen measuring 7.7 cm, roughly 3.0 in. Diamond darters bear a strong resemblance to crystal darters, their relatives.

The red-bellied piranha belongs to the family Serrasalmidae, which is a group of medium to large-sized characids and includes other closely related omnivores such as pacus.Black-finned Pacu Fish, Colossoma macropomum: Profile with care, maintenance requirements and breeding information for your tropical fish. Badmanstropicalfish.com. Retrieved on 2012-05-13. They are characterized by deep, lateral compressed bodies and long dorsal fins.

Dark bars run from the eyes down. There are also dark bars on the dorsal fins, caudal fins, and anal fins. The large eyes and thick lips give the decorated warbonnet an almost cartoon like look. They have 61 or 62 total dorsal spines, 0 dorsal soft rays, 1 anal spine, and anywhere from 44 to 51 anal soft rays.

The body shows typical halfbeak shape with an elongated lower jaw and cylindrical elongated body. They have no spines on fins, but do have 13-14 rays of their dorsal fins and 12-13 rays on their anal fins. The longest recorded Jumping halfbeak was 55 cm long, but most do not exceed 35 cm. There is no ridge between nostril and eye.

The nostrils are located near the ends of the cephalofoil, with long grooves running towards the center. There are 26-32 tooth rows in the upper jaw and 25-30 tooth rows in the lower jaw. Each tooth is triangular in shape, with smooth to weakly serrated edges. The body is streamlined, without a dorsal ridge between the two dorsal fins.

They also possess two dorsal fins with separate bases, as opposed to the single dorsal fin of ray- finned fish. The coelacanth is a lobe-finned fish which is still extant. It is thought to have evolved into roughly its current form about 408 million years ago, during the early Devonian. Locomotion of the coelacanths is unique to their kind.

No other group of electric rays have genera with a variable number of dorsal fins. The tail is moderately long, with a large, rounded, symmetrical caudal fin. The color is usually brown or reddish brown above, white or brownish below. There may be spots, blotches, or bands on the dorsal surface, but most species lack complex color patterns or ocelli.

The hardnose shark is slender, with a long snout and elongated rear tips on the dorsal fins. The hardnose shark is a slim-bodied species with a long, narrow, and pointed snout. Unlike in other Carcharhinus species, its rostral (snout) cartilages are highly calcified, hence the name "hardnose". The circular eyes are rather large and equipped with protective nictitating membranes.

It has two dorsal fins that help differentiate this shark from other Oxynotus species. Its first dorsal fin is inclined forward, is very long and thick, and triangular in shape. The second dorsal fin is similar to the first, although it is not as long. However, as some other Oxynotus species, the Caribbean roughshark does not have an anal fin.

They are nocturnal piscivorous drift-hunters. The body is covered in cosmoid scales that act as armor. Coelacanths have eight fins – 2 dorsal fins, 2 pectoral fins, 2 pelvic fins, 1 anal fin and 1 caudal fin. The tail is very nearly equally proportioned and is split by a terminal tuft of fin rays that make up its caudal lobe.

Upper teeth Lower teeth C. longimanus most distinguishing characteristics are its long, wing-like pectoral and dorsal fins. The fins are significantly larger than most other shark species, and are conspicuously rounded. The shark's nose is rounded and its eyes are circular, with nictitating membranes. C. longimanus has a 'typical', although somewhat flattened requiem shark body, often with a mildly humpbacked aspect.

The fairly long and pointed pectoral fins are slightly sickle-shaped (falcate) and originate between the fourth and fifth gill slits. The first dorsal fin is medium-sized and triangular with a pointed apex, and originates over the rear of the pectoral fin bases. The second dorsal fin is small and positioned opposite the anal fin. No ridge exists between the dorsal fins.

The Coastrange sculpin can be distinguished from other species due to several unique traits. It only has one pore under its chin, no palatine teeth, and no distinct gap between the two dorsal fins. Adults can grow to be as long as 17 cm, although their average length is only 6 cm. Their maximum reported life span is 8 years.

The small pectoral fins are falcate (sickle-shaped) with relatively pointed tips. The first dorsal fin is broad, forming nearly an equilateral triangle in adults, with a blunt apex; it originates over the pectoral fin rear tips. The second dorsal fin is small and originates over the midpoint of the anal fin base. No ridge exists between the dorsal fins.

The five pairs of gill slits are small and placed beneath the disc. The pelvic fins are small and have blunt outer corners. The moderately thick tail measures 93–102% as long as the disc and lacks lateral skin folds and dorsal fins. One or two serrated stinging spines are present atop the tail, just ahead of the halfway point.

It has a long, strong tail and two dorsal fins. The first dorsal fin is broad, while the second is slightly smaller and more slender. Its teeth are distributed in up to 38 rows and it has visible flaps on its nostrils. It has rounded spiracles, a feature that does not appear in any other species in the genus Torpedo.

The Vibranium fairy wrasse (Cirrhilabrus wakanda) is a species of fairy wrasse from the Western Indian Ocean. The species shares a combination of characters including short pelvic fins, and unmarked anal and dorsal fins. It was first collected off the coast of Zanzibar, Tanzania at depths of more than 60 meters by scientists from the California Academy of Sciences. It inhabits coral reefs.

It has dense sturdy spines from its nose to halfway between its pectoral and dorsal fins. It has greyish or greenish upperparts dotted with lighter and darker dots and dark bands. The chin is yellowish and belly is white. There is a dark brown stripe running from the base of the pectoral fin to the tail fin along the fishes sides.

The body shows typical halfbeak shape with an elongated lower jaw and cylindrical elongated body. They have no spines on fins, but do have 12-15 rays of their dorsal fins and 10-13 rays on their anal fins. The longest recorded Jumping halfbeak was 34 cm long. There are no vertical bars on sides of the body as other halfbeaks.

As the darters grow and mature, they take on the characteristics of their sex. They mature and become of breeding age in one to two years, and usually do not live longer than four years. The males of this species have modified first dorsal fins that characteristically look like little bulbs. This is believed to be used for egg mimicry purposes.

Gobiomorphus is a genus of fishes in the family Eleotridae native to New Zealand and Australia. They are typically small, benthic fishes with large, rounded fins and two dorsal fins. Many have an amphidromous lifecycle: the eggs are laid in fresh water, but the fry are dispersed to sea soon after hatching, and grow there for several months before returning to fresh water.

Bluegills have the ability to travel and change directions at high speeds by means of synchronized fin movements. They use notched caudal fins, soft dorsal fins, body undulations, and pectoral fins to move forward. Having a notched caudal fin allows them to accelerate quickly. The speed of their forward motion depends on the strength of which they abduct or adduct fins.

It can be challenging to tell male and female apart in the wild for many cetacean species. Long-finned pilot whales are no exception, though it was thought in the past that males had hooked dorsal fins while females did not. Recent research on fin shape has shown that this is not a predictable way to distinguish between the sexes.

Pseudomugil is a genus of fish in the subfamily Pseudomugilinae endemic to Australia and New Guinea, where they are found in freshwater rivers and streams and bodies of brackish water. Members of this genus have slender bodies and two dorsal fins. They are usually sexually dimorphic.Saeed, B., Ivantsoff, W. & Allen, G.R. (1989): Taxonomic Revision of the Family Pseudomugilidae (Order Atheriniformes).

The five pairs of gill slits are tiny and of uniform width. The two dorsal fins lack spines. The first dorsal originates over the pectoral fin bases; the second dorsal is slightly larger than the first but is about equal in base length, and originates over the middle of the pelvic fin bases. The pectoral fins are short and somewhat paddle-like.

The pelvic fins are rather long and narrow; males have slender claspers that have a fleshy flap at the tip. The first dorsal fin base is located roughly over the latter half of the pelvic fin bases. The second dorsal fin is smaller and more angled than the first. The dorsal fins have more rounded apexes in females than males.

The fishes in the subfamily Serraninae, the serranines, are small species within the family Serranidae. They generally have ten spines in their dorsal fins and seven soft rays in their anal fins. They are also characterised by the fin spines being unserrated. The genera within the Serraninae are separated by the counts of the soft rays in the dorsal fin.

Callionymus belcheri has a yellowish to brown head and body with many small white spots on its back. The flanks are marked with white blotches which have dark brown margins. The underside is white. There are two dorsal fins, the first dorsal fin is brownish in colour, with a distal margin that is often blackish and which in males has white spots.

Two Iowa darters, male (on left) and female (on right). The Iowa darter has a very slim, small body. Its common length is around 5.5 cm and its maximum age is three years. It has a small mouth and snout with scaled opercles and cheeks, two dorsal fins, one which is a spinous-rayed fin and another soft-rayed fin.

This ghostshark has a compressed, elongate body, which thins out to its tail. It is medium-brown in color, with a lighter underside and a darker upperside. Most of its fins are dark, including its two dorsal fins, while its lower tail is white. It is covered with blotches of white, which can be circular, narrow, or elongate in shape.

Their deep, laterally narrow bodies are easily noticed through the profusion of reef life. The conspicuous colouration of butterflyfish may be intended for interspecies communication. Butterflyfish have uninterrupted dorsal fins with tail fins that may be rounded or truncated, but are never forked. Generally diurnal and frequenting waters of less than (though some species descend to ), butterflyfish stick to particular home ranges.

Atlantic spotted dolphin The Delphinidae are the most diverse of the cetacean families, with numerous variations between species. They range in size from and (Haviside's dolphin), to and 10 tonnes (killer whale). Most species weigh between . They typically have curved dorsal fins, clear 'beaks' at the front of their heads, and forehead melons, although exceptions to all of these rules are found.

The short and thick tail bears skin folds along either side and two dorsal fins on top. The first dorsal fin is slightly larger than the second. The well-developed caudal fin is triangular with blunt corners, and is approximately as long as the space between it and first dorsal fin. The skin is smooth and soft, entirely lacking dermal denticles.

Both dorsal fins show a blackish anterior margin with the remaining parts of the fins translucent and slightly dusky. The membranes of the pectoral fins are vivid yellow in smaller individuals but in larger fish this becomes duskier. The pectoral filaments are white. The pelvic fins are white with a yellow front edge while the caudal fin is blackish with a yellowish base.

The most sensitive areas of the body are around the eyes, nostrils, fleshy parts of the tail, and pectoral and dorsal fins. Rainbow trout also have corneal nociceptors. Out of 27 receptors investigated in one study, seven were polymodal nociceptors and six were mechanothermal nociceptors. Mechanical and thermal thresholds were lower than those of cutaneous receptors, indicating greater sensitivity in the cornea.

This species has 32–38 of these ctenoid lateral scales. Their tails, dorsal fins, and other fins are rounded or squared. The dorsal fin has two lobes, slightly separated, the first with five to seven spines and the second with 9–10 rays. The pelvic fins are thoracic, and their anal fins have one or two spines and five or six rays.

The native Mozambique tilapia is laterally compressed, and has a deep body with long dorsal fins, the front part of which have spines. Native coloration is a dull greenish or yellowish, and weak banding may be seen. Adults reach up to in standard length and up to . Size and coloration may vary in captive and naturalized populations due to environmental and breeding pressures.

The congolli is a slender, mottled fish, with a silvery-white underside. Its head is slightly flattened, with eyes positioned towards the top and the snout is pointed. It has two separate dorsal fins. The colour varies according to where it lives: it may be bluish, purplish or reddish-brown, marbled with greenish-brown above, and a yellowish white to silvery colour below.

The two dorsal fins were said to be over six feet high, with a large pair of flippers. It was provisionally named Anphiptera Pacifica, and is an unrecognized species of, not having been confirmed by enough sightings to be recognized as a species. Magenta was. The voyage of the "Magenta" was sponsored by the Government of Italy in the 19th century.

The pectoral fins are large, but not clearly demarcated from the body, and together with the body are known as the disc. They start from the side of the head in front of the gill openings and end at the caudal peduncle. There are up to two dorsal fins but no anal fin. A slender tail is clearly demarcated from the disc.

The 1967 Yonggary has a bipedal reptilian design with a long horn on his snout, tusks at the side of his mouth, a single row of dorsal fins, and spikes on the side of his tail. The 1967 Yonggary is capable of breathing fire and his primary food source is oil and gasoline.Yongary, Monster from the Deep (1967). Directed by Kim Ki-duk.

The three species can be differentiated by physical differences between them. One defining difference is, although both species have white around the mouth, on pygmy killer whales the white extends back onto the face. Pygmy killer whales also have rounded-tipped dorsal fins, as opposed to pointed tips. When compared to false killer whales, pygmy killer whales have a larger dorsal fin.

The fish is silvery in colour with iridescent reflections and dark, variable markings on the sides. Males mature at and females at , and the maximum length head to tail is . It has an elongated body, smooth and torpedo shaped with two widely separated, triangular dorsal fins. They use their hoe-shaped snouts to probe the ocean bottom for invertebrates and small fishes.

Ophidiiform fish typically have slender bodies with small heads, and either smooth scales, or none at all. They have long dorsal fins, and an anal fin that is typically united with the caudal fin. The group includes pelagic, benthic, and even parasitic species, although all have a similar body form. Some species are viviparous, giving birth to live young, rather than laying eggs.

The three upper and two lower rows of symphysial (central) teeth are especially long and fang-like. The five pairs of gill slits are short. The pectoral and pelvic fins are large and rounded. The dorsal fins are short-based and fairly tall; the first is slightly larger than the second and originates over the latter quarter of the pelvic fin bases.

The fins are strongly falcate (sickle-shaped), particularly the dorsal fins, pelvic fins, and lower caudal fin lobe. The pectoral fins are narrow and pointed. The first dorsal fin is positioned about halfway between the pectoral and pelvic fins. The second dorsal fin is about two-thirds as tall as the first and is positioned slightly ahead of the anal fin.

Pearl blennies are pale in colour marked with dark brown bands and have extremely bright white spots along the length of theor whole bodies. They have a blunt head and a high forehead with two moderately-sized eyes. They have filaments over the eyes and on the nape which are called cirri. When breeding the male's cirri and dorsal fins become enlarged.

Many will also inhabit empty clam shells, which also serve as nesting sites; males are known to guard the brood. Some species have dorsal fins which are significantly higher towards the head, explaining the moniker "flagblenny". Crustaceans make up the bulk of the chaenopsid diet. At least one species found in the Caribbean, Emblemariopsis diaphana, is known to form a symbiotic relationship with stony coral, Meandrina meandrites.

The spines of the anal and paired fins have scattered black/dark spots near the base. The membranes of the pectoral and pelvic fins are cream to yellow. The base of the caudal fin is usually white to yellow in color. The males can have submarginal bands in the spinous (harder or tougher fins near the base) and soft dorsal fins and also on the caudal fin.

The pectoral fins are small, broad, and rounded; the pelvic fins are similar and almost as large. The two dorsal fins have straight trailing margins and are spaced well apart. The first dorsal fin is as large or larger than the pelvic fins, originating behind the middle of the pelvic fin bases. The second dorsal fin is slightly smaller than the first but has a longer base.

Externally, it has a greater size difference between its dorsal fins (first-to-second height ratio >3.1:1 versus ≤3.1:1 in C. leucas) and the notch in its anal fin margin forms an acute angle (versus a right angle in C. leucas). This species also usually has fewer tooth rows in the lower jaw (10–12 on each side versus 12–13 in C. leucas).

This species is bronze above and white below, which extends onto the flanks as a pale stripe. The pectoral fins, dorsal fins, lower caudal fin lobe, and sometimes the pelvic fins usually have black tips, while the upper caudal fin lobe darkens towards the trailing edge and the anal fin may be completely light. The fin markings tend to fade with age. The maximum known length is .

The first dorsal fin originates over the free rear tips of the pectoral fins; it is large and falcate (sickle-shaped) with a pointed apex. The second dorsal fin is positioned opposite the anal fin and is relatively large and high. There is no ridge between the dorsal fins. A crescent-shaped notch is present on the caudal peduncle just before the upper caudal fin origin.

It is similar to other rough sharks in having a stout, high trunk, a dorsally depressed head, and two sail-like dorsal fins with deeply embedded spines. The snout is short, with large nostrils whose lateral and medial apertures are separated by a thick nasal flap. The eyes and spiracles are oval in shape. The five pairs of gill slits are very small and vertical.

Princeton Field Guides Oxynotus centrina has a compressed body, triangular in cross section, with a broad and flattened head. The snout is flat and blunt. Just like all of the Oxynotus species, they have two relatively large dorsal fins that are sail-like, and no anal fin. Their color scheme is grey ogayr grey-brown dorsally with dark blotched on its head and sides.

Dorsal fins also exhibit sexual dimorphism, with those of males about high, more than twice the size of the female's, with the male's fin more like a tall, elongated isosceles triangle, whereas the female's is shorter and more curved.Orca (Killer whale). American Cetacean Society. Retrieved January 2, 2009 Males and females also have different patterns of black and white skin in their genital areas.

A silver midlateral, longitudinal stripe is normally present. The dorsal fins are dusky on each end, with or without rows of dark brown spots on the second dorsal fin membranes. The caudal fin is dusky terminally, and there is no dark blotch at the base of the pectoral fin as in other sillaginids. All other fins are hyaline, but the anal fin occasionally has a whitish margin.

The teeth are molar-like with low cusps. Both the dorsal fins have a curved trailing edge and the distance separating them occupies about 20% of the total length of the fish. The dorsal surface and flanks are grey or greyish-brown and the ventral surface is paler. The colour is uniform and there are no spots or bands of darker or lighter colour.

The speckled smooth-hound is a robust shark with a moderately long, blunt snout, small eyes, short mouth and molar-like teeth without cusps. The trailing edge of the dorsal fins have small, pointed projections. The pectoral fins are large and the pelvic fins moderately large. The caudal peduncle is short and the lower lobe of the tail fin is narrow and slightly curved.

A moderately rough covering of dermal denticles is present over the upper surface and both dorsal fins; the underside is mostly smooth, except along the pectoral and pelvic fin margins. This species is greenish brown above with many round, pale-edged brown spots, black saddles below the dorsal fin bases, and white pelvic fin edges. It is plain white below. The sole specimen measures long.

The two dorsal fins are positioned about between the pectoral and pelvic fins. Each dorsal fin bears a slightly grooved spine in front; the second dorsal spine is longer than the first. The anal fin is absent, and the caudal peduncle lacks keels or notches. The upper lobe of the caudal fin is larger than the lower and has a notch in the trailing margin.

T. vagina has an elongated body about in length. The anal, caudal, and two dorsal fins are fused together with membranous structures, forming a continuous margin around the posterior of the body. The pelvic fins are also completely fused together to form a cup-shaped suction disk. The pectoral fins have fifteen to twenty rays, with the upper rays longer than the lower rays.

Trypauchen pelaeos is a species of eel goby found in Indochina and southern China. It is reddish in color and has an elongated body with the anal, caudal, and the two dorsal fins fused together with membranous structures. It is similar in appearance and habits to the closely related burrowing goby, Trypauchen vagina. T. pelaeos was first described by Edward O. Murdy in 2006.

It possesses two spiny dorsal fins, which are spaced far apart, two pectoral fins, and small caudal and anal fins, also spaced far apart. 4-6 dorsal finlets and 5 anal finlets are typical among members of this species. The fish's body tapers down its length, ending with a large tail fin. Typical size for a mature fish is , but individuals have been caught as large as .

These small scales give the Atlantic mackerel a velvet-like feel. The two dorsal fins are large and spaced far apart. The second dorsal fin is typically followed by 5 dorsal finlets, though it can have 4 or 6. The anal fin, which originates slightly behind the second dorsal fin, is similar to it in size and shape and is also succeeded by 5 finlets.

Tailring cardinalfish is a small sized fish which grows up to 7 cm. Its body has an elongate appearance, compressed laterally and with a round profile. It has two translucide dorsal fins, one lateral line, a large mouth and big round eyes.Lieske & Myers,Coral reef fishes,Princeton University Press, 2009, Its body coloration is silver grey with a black ring around the caudal peduncle.

The first three teeth in each jaw are enlarged into canines. A small lower spine occurs on the preoperculum. The pectoral fins are long, with 12–15 (usually 13) rays; the pelvic fins are small and contain five rays. Of the two dorsal fins, the first is spiny with 10–12 spines, and the second is longer with one spine and 26–29 soft rays.

The common goby has two dorsal fins with a narrow gap between them, the anterior one consisting of six to eight spines and the posterior one eight to eleven soft rays. The pelvic fins are fused. There are 39 to 51 scales along the lateral line and these scales are slightly larger than those of the sand goby (Pomatoschistus minutus). The caudal fin is rounded.

The largest member of its family, the black dogfish, typically measures long. It has a stocky, dark brown body that is darker below than above, and bears scattered, minute bioluminescent organs. Its two dorsal fins are preceded by stout spines, and the anal fin is absent. Active and schooling, the black dogfish is an opportunistic predator and scavenger that mainly consumes bony fishes, crustaceans, and cephalopods.

Coryphaena is a genus of marine ray-finned fishes known as the dolphinfishes. This genus is currently the only known genus in its family. The species in this genus have compressed heads and single dorsal fins that run the entire length of the fishes' bodies. Dolphinfishes are some of the fastest-growing species in the ocean, so serve as a primary food source for many pelagic predators.

Ailiidae is a family of catfishes native to Asia.Wang, J., Lu, B., Zan, R., Chai, J., Ma, W., Jin, W., Duan, R., Luo, J., Murphy, R.W., Xiao, H. & Chen, Z. (2016): Phylogenetic Relationships of Five Asian Schilbid Genera Including Clupisoma (Siluriformes: Schilbeidae). PLoS ONE, 11 (1): e0145675. These fishes usually have dorsal fins with a short base and a spine, but Ailia lack a dorsal fin altogether.

Female dorsal fins are slightly larger than the male's and are located lower on the back. The eyes of the lined seahorse can concentrate together, or they can operate independently of one another. The lined seahorse may be considered sexually mature as early as four months; however, it is typically about eight months. The minimum size of a sexually mature lined seahorse is 5.6 cm.

The gills are small and occur only on the sides of the fish. The pelvic fins are forward of the pectoral fins, usually under the gills, and have one spine with several soft rays. For the two separate dorsal fins, the first is smaller with spines, while the second has from 15 to 25 soft rays. The number of vertebrae range from 25 to 47.

The first dorsal fin of the Atlantic bonito is also lower and sloping. Its lack of teeth on the vomer can set it apart from its close Pacific relatives, the kawakawa and the black skipjack. The dorsal fins of the bullet and frigate mackerel are set apart. Unlike the little tunny, the skipjack tuna lacks markings on the back and has broad, straight stripes on the underside.

The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. pardalis, the spine of the dorsal fin is about as long as the head, slightly curved, smooth in the front and serrated on the back.

The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. longirostris, the spine of the dorsal fin is about the length of the head, slight curved, smooth in the front and serrated on the back.

The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. guttatus, the spine of the dorsal fin is about the length of the head, smooth in the front and serrated on the back.

Locomotion in the grey triggerfish is by means of undulations of the dorsal fins. If threatened, the fish can work its way into a protective crevice and wedge itself in place by erecting its front dorsal spine. It is difficult to dislodge from this position. The second spine is connected to the first and when it is depressed, it triggers the unlocking of the first spine.

The eyes are large, with a rudimentary nictitating membrane (protective third eyelid) and a prominent ridge beneath. The five gill slits are positioned somewhat dorsally on the body. The dorsal, pelvic, and anal fins are of roughly equal size. The dorsal fins are placed far back on the body, with the first originating behind the pelvic fin origins and the second originating behind the anal fin origins.

The gill covers do not have spines and are covered with small scales. The two dorsal fins are widely separated, with the first having five spines and the second having one spine and 9 soft rays. The second dorsal fin equals the anal fin in size and is situated more or less above it. The lateral line is prominent and extends straight from head to tail.

Its abdomen is usually a whitish-red color. During the off-breeding seasons, males can be identified by prominent, variously colored bands on their anal and dorsal fins. The caudal fin is a "dusky" colour, and the pectoral and pelvic fins have no colour. During the breeding season, the male's colors brighten significantly, turning a red-orange colour, and they sometimes appear to glow.

Family members are distinguished by having a laterally compressed body shape, 3 to 8 anal spines, and 2 dorsal fins (spinous first dorsal and rayed second dorsal) which are fused. The number of dorsal spines varies from 6 to 13. All species in Micropterus and Lepomis have 3 anal spines, which distinguishes them from the other genera in the family. The pseudobranch is small and concealed.

The mackerel, tuna, and bonito family, Scombridae, includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies. All species are in the subfamily Scombrinae, except the butterfly kingfish, which is the sole member of subfamily Gasterochismatinae. Scombrids have two dorsal fins and a series of finlets behind the rear dorsal fin and anal fin.

The Indian threadfin is a large species with an elongated head and body. Its eye is roughly the same size as the length of its snout. The joint of the jaws is to the rear of the eyelid. It has two separated dorsal fins, the first dorsal fin contains 8 spines while the second dorsal fin has a single spine and 12 or 13 soft rays.

The snout and abdomen are blackish. The membranes of first and second dorsal fins and caudal fin are blackish with their outer portions being black. The membrane of the pectoral fin is deep black with the base of the filaments being dusky yellow, darkening to the rear. The pelvic fin is also dusky yellow at its base and dirty white on its other parts.

The red-lined wrasse can grow to about in length. Mature males are silvery grey with narrow, longitudinal, red stripes and a dark mark on their caudal peduncles. Females have narrow orange stripes, continuous near the front, but intermittent near the back. Juveniles and females have two distinctive, dark-coloured spots outlined in white on their dorsal fins, one in the middle and one near the back.

The five pairs of gill slits are short. The pelvic fins are small and rounded. The tail measures 71-91% of the disc length, has a flattened oval cross-section, and terminates in a low leaf-shaped caudal fin. The tail bears a serrated stinging spine on the dorsal surface about midway along its length; there are no dorsal fins or lateral fin folds.

Butterflyfish have deep, laterally flattened bodies, a slightly upturned snout, uninterrupted dorsal fins and unforked, broadly wedge-shaped tail fins with flat ends. Chaetodon litus has a rectangular outline and is silvery-grey with white-edged scales. The maximum length is long. The dorsal fin has 13 spines and 23 to 25 soft rays while the anal fin has 3 spines and 19 or 20 soft rays.

Corydoras narcissus is a tropical freshwater fish belonging to the Corydoradinae sub-family of the family Callichthyidae. It originates in inland waters in South America, and is found in the Purus River in the central Amazon Basin in Brazil. It is commonly known as the Long Nose Arched Cory. These fish are identifiable by the two dark stripes that run alongside their dorsal fins.

Carpet sharks are sharks classified in the order Orectolobiformes. Sometimes the common name "carpet shark" (named so because many species resemble ornately patterned carpets) is used interchangeably with "wobbegong", which is the common name of sharks in the family Orectolobidae. Carpet sharks have five gill slits, two spineless dorsal fins, and a small mouth that does not extend past the eyes. Many species have barbels.

It has slot-like body openings called gill slits on the underside of the body beneath the pectoral fins that lead from the gills. The dorsal fins are close together and far removed from the tail. It has two eyes on its dorsal surface, located about apart. The fish's upper surface is brown to reddish brown with many scattered darker spots, lighter streaks, and reticulations.

The Japanese sturgeon, or Amur sturgeon (Acipenser schrenckii) is a species of fish in the family Acipenseridae found in the Amur River basin in China and Russia. Claims of its presence in the Sea of Japan need confirmation. The species has 11–16 dorsal, 34–47 lateral, and 7–16 ventral scutes. Their dorsal fins have 38–53 rays and 20–35 anal fin rays.

The morphology of tetrapodomorphs, fish that are similar- looking to tetrapods, give indications of the transition from water to terrestrial life. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. The first tetrapod land vertebrates, basal amphibian organisms, possessed legs derived from these fins. Sarcopterygians also possess two dorsal fins with separate bases, as opposed to the single dorsal fin of actinopterygians (ray-finned fish).

Workers have established that this subfamily is monophyletic. They have a pelvic fin which has a single spine and three or four unbranched soft rays, their heads are covered in scales, most of the rays in their dorsal fins are simple, they have teeth on the palatine bone; their pectoral fins have 17–19 rays and the lateral line has one anterior-pored scale.

It has two dorsal fins; the anterior being quite short while the posterior dorsal fin stretches more than half the body length. The caudal (tail) fin is rounded and not overly wide. The ventral aspect of the body is described as silver in color while the dorsal section is a pale pink-brownish color. The eyes are large and a barbel is present on the chin.

Platyrhina species have rounded, heart-shaped pectoral fin discs with short, blunt snouts. Their tails are long and shark-like, slightly flattened with lateral ridges. The two dorsal fins and the caudal fin are large and rounded; the caudal fin lacks a lower lobe. The teeth are small and arranged in pavement- like rows for crushing shelled prey.中国团扇鳐. 百度百科.

Eleutheronema tetradactylum has two dorsal fins the first has 9 spines and the second has 13-15 soft rays with 13 being the mean. The anal fin has 3 spines and 14-19 soft rays. The pectoral fins have 16-18 rays and there are 4 pectoral filaments. The upper sides of the head and body have a slight darkish silver tinge, lighting in the lower flanks.

Squalidae, also called dogfish sharks, dog sharks, or spiny dogfish, are a family of sharks in the order Squaliformes. Dogfish sharks make up the second largest order of sharks at 119 species. They have two dorsal fins, each with smooth spines, but no anal fin, and their skin is generally rough to the touch. Dogfish tend to have slender bodies with a pointed snout.

Mordacia praecox, the Australian brook lamprey or nonparasitic lamprey, is a freshwater species of southern topeyed lamprey that occurs in south-eastern Australia. It has a thin eel-like body around 12 to 15 cm long, with two low dorsal fins on the back half. The skin is dark blue above and gray below. Its eyes are small, and located on the top of its head.

There are cartilaginous plates inside the mouth and the central, lingual plate has nine to thirteen teeth, a fact that distinguishes it from other lamprey species. The single nostril is between the eyes and seven naked gill pores are behind them. The only fins are two dorsal fins that run most of the way along the spine, and a small diamond- shaped tail fin.

The snakeheads are members of the freshwater perciform fish family Channidae, native to parts of Africa and Asia. These elongated, predatory fish are distinguished by their long dorsal fins, large mouths, and shiny teeth. They breathe air with gills, which allows them to migrate short distances over land. They have suprabranchial organs, which are primitive forms of labyrinth organs, that develop when they grow older.

The two close-set dorsal fins usually have an interdorsal thorn. Its coloration is grayish purple to dark chocolate brown or black above, occasionally with scattered small, darker spots, and slightly darker below except for a whitish area around the mouth. The anterior tips of the pelvic fins are whitish. Large males have irregular whitish blotches and numerous dark spots, while females have reduced or absent blotches.

Distinctive characters include two dorsal fins widely separated, with the first consisting of flexible spines and the second having one spine followed by soft rays, while the anal fin has one spine on the leading edge followed by soft rays. The pectoral fins tend to be high, and there is no lateral line. On the flanks is a broad, silvery band. The scales are relatively large.

Members of the family are generally small, with some ranging up to 40 cm, but most no more than 15 cm. They have two dorsal fins, the first with seven to 10 spines and the second with possibly a spine in addition to eight to 10 soft rays. The anal fin has two or three spines, and the pelvic fins one spine and five soft rays.

Juveniles and some adults have two silvery-white spots (hence the common name) on the back close to their dorsal fins, while larger adults lose the spots and become mostly red. Large adults may cause ciguatera poisoning.Dianne J. Bray, 2011 Red Bass, Lutjanus bohar, in Fishes of Australia This species is a commercially important species and is also sought-after as a game fish.

Like all lampreys, these fish lack paired fins and possess a circular sucking disc instead of jaws, which is filled with blunt teeth. They have a single nostril and seven small gill openings on either side behind the eye. The brook lamprey can be told from the closely related river lamprey (Lampetra fluviatilis) by the fact that its two dorsal fins are more closely linked together.

It has two nearly contiguous dorsal fins; the first is short based and high, and the second is long-based, extending to the base of the caudal fin. It may grow up to . It has been found in the Tasman Sea, around Australia from Queensland to the north Western Australian shelf and off the New Zealand shelf at depths of . It has no commercial value.

The escolar is dark brown, growing darker with age until it is quite black. It is a fast-swimming fish with a prominent lateral keel and four to six finlets after the anal and second dorsal fins. Escolar can grow to over 2 m in length. Like its relative the oilfish (Ruvettus pretiosus), escolar cannot metabolize the wax esters (gempylotoxin) naturally found in its diet.

Males reach maximum lengths of , but are usually less than , while the females are usually smaller. They have a slender and compressed body shape. Crimson-spotted rainbowfish have two dorsal fins very close together, with the first much smaller than the second. Their fin colours vary from clear to yellowish to red, with red flecks and dark margins which become intensely black in males during spawning activities.

One of its two dorsal fins is short in length but tall, while the other is lower and longer. Its caudal fin is long, and contains denticles on its upper lobe. It has a brown upperside and a more greyish-brown underside, with a white snout. The edges of the fins tend to be darker in color, ranging from a dark brown to purple color.

Narrownose chimaeras have elongate rostra, slender tails, large pectoral and pelvic fins, large eyes, and two dorsal fins, the first being preceded by a spine. They possess two pairs of non-replaceable tooth plates in the upper jaw and a one pair in the lower jaw.Didier, Dominique A. "Phylogeny and classification of extant Holocephali." Biology of sharks and their relatives 4 (2004): 115-138.

Bowfins have many-rayed dorsal fins and can breathe air like the bichirs. The gars have thick ganoid scales typical of sturgeons whereas the bowfin has thin bony scales like the teleosts. The gars are therefore in this regard considered more primitive than the bowfin. The name Holostei derives from the Greek, holos meaning whole and osteon meaning bone: a reference to their bony skeletons.

The caudal fin is asymmetrical, with a long upper lobe and a well-developed lower lobe; the trailing margins of both lobes are convex. The skin is covered by tiny, non- overlapping dermal denticles. Unlike other Squalus species, adults have a mix of one-cusped and three-cusped denticles. This species is dark brown above, darkening towards the apexes of the dorsal fins, and pale below.

A straight lateral line is positioned roughly near the center of their sides. These fish also have eight anal fin rays on the tail fin, which is a forked version of a homocercal tail. The dorsal fin lies behind the middle of the body. The dorsal fins of all soft-rayed teleosts are supported by soft, flexible rays, and this shiner is no different.

Dorsal fins tend to be high, with a rather short base (9-13 rays, but in some as few as three); they are placed just behind the head. They have seven branchiostegal rays. The species have a range of sizes, the longest reaching . Most of the species are poorly known, but the highfin tadpole fish (Guentherus altivelis) is of potential interest for commercial fishing.

The Atlantic wreckfish is a large fish with a deep, robust body and a large head with a protruding lower jaw. The two dorsal fins are joined, the first has 11 spines with the final spine joined on to the second dorsal fin, which has 12 branched rays. The anal fin has a short base and has three robust spines. The caudal fin is broad and square.

B. moresbyi is a relatively small electric ray, with males reaching a maximum size of 35.12 centimeters and females a maximum size of 39.24. Its body is entirely dark brown in color. The caudal fin of the species is very long, almost 1/2 the length of its tail. Its dorsal fins have large bases compared to their height, and are located close together.

The ornate rainbowfish is a small, slender and rather elongated species of rainbowfish. It has two dorsal fins that are only narrowly separated, and the first dorsal fin is considerably smaller than the second. There are 3 to 5 thin, soft spines in the first dorsal fin while the second dorsal fin has 11–15 segmented rays. This species is highly variable in colour over its range.

There are around 59 tooth rows in the upper jaw and 62 tooth rows in the lower jaw. The pectoral fins are moderately large and wide, with rounded tips. The dorsal fins have rounded apexes and are placed well back on the body, the first originating behind the midpoints of the small pelvic fins. The first dorsal fin is about twice as high as the second.

The diamond tetra (Moenkhausia pittieri) is a small freshwater fish of the characin family (family Characidae) of order Characiformes. It is found in and around Lake Valencia in Venezuela, South America. This species exhibits clear sexual dimorphism, with males having much longer dorsal fins than the females. Males also tend to be more brightly coloured, but both sexes are attractive fish and have become popular with aquarists.

Close-up from above of the caudal fin denticle crest of the longfin sawtail catshark (G. cadenati); such crests are shared by all Galeus species. The two dorsal fins are nearly equal in size and shape, and are placed well back on the body, behind the origins of the pelvic fins. The pectoral fins are fairly large and broad, with angular to rounded corners.

Merlangius merlangus has three dorsal fins with a total of 30 to 40 soft rays and two anal fins with 30 to 35 soft rays. The body is long and the head small and a chin barbel, if present, is very small. This fish can reach a maximum length of about . The colour may be yellowish-brown, greenish or dark blue, the flanks yellowish grey or white and the belly silvery.

Blenniformids are generally small fish-only occasionally reaching lengths up to 55 cm, with elongated bodies (some almost eel-like), and relatively large eyes and mouths. Their dorsal fins are often continuous and long; the pelvic fins typically have a single embedded spine and are short and slender, situated before the pectoral fins. The tail fin is rounded. The blunt heads of blenniiformids often possess elaborate whisker-like structures called cirri.

The bottom and top edges of the tail fin are edged with white. The male has extended filaments on its dorsal, anal and pelvic fins. There are black markings at the base of the anterior rays of the anal and rear dorsal fins, and the front (anterior edge) is sometimes white and the rear (posterior) edge greyish in colour. The male's fins may turn orange during breeding season.

The first dorsal fin has an orange stripe at its base and a wider and darker reddish brown stripe at its tip. The second dorsal fin has a number of reddish stripes. The lobes of the tail are marked with indistinct crossbars. There are a total of 9 spines in the dorsal fins and 8 soft rays while the anal fin has 2 spines and 6 soft rays.

The Indo-Pacific sailfish has a prominent dorsal fin. Like scombroids and other billfish, they streamline themselves by retracting their dorsal fins into a groove in their body when they swim. The huge dorsal fin, or sail, of the sailfish is kept retracted most of the time. Sailfish raise them if they want to herd a school of small fish, and also after periods of high activity, presumably to cool down.

The finless sleeper ray (Temera hardwickii) is a species of electric ray in the family Narkidae, and the sole member of its genus. It is found over the continental shelf of Southeast Asia from the eastern Andaman Sea to Vietnam and Borneo. Typically growing no more than long, it may be the smallest cartilaginous fish. The finless sleeper ray is the only electric ray that lacks dorsal fins.

It has a long, broad snout with prominent nasal skin flaps, and tall, triangular upper teeth. Its pectoral fins are long and almost straight, and there is a ridge on its back between the two dorsal fins. Hunting close to the sea floor, the bignose shark feeds on bony and cartilaginous fishes, and cephalopods. It is viviparous, meaning the embryos are sustained to term via a placental connection.

The mouth is short and curved, with furrows at the corners extending onto both jaws. The teeth have a central cusp and smaller lateral cusplets. The five pairs of gill slits are located on the upper side of the body. The two dorsal fins are set far back on the body, the first originating behind the pelvic fin midbases and the second originating behind the anal fin midbase.

The starry smooth-hound grows to a length of about . It is grey or greyish-brown with a scattering of small white spots on its dorsal (upper) surface and white on its ventral (under) surface. It is a long, lean fish with a somewhat rounded snout and rows of shallowly projecting teeth. The two dorsal fins are of similar shape, but the hindmost one is a little smaller than the foremost.

Although fairly similar, there exist some differences between both species. Baird's beaked whales are around 4.6 meters when born, and can reach lengths of 11.1 meters as adults, making them the largest members of the beaked whale family. Female Baird's and Arnoux beaked whales are slightly larger than the males. Baird's have fairly narrow body shapes despite their large size, and have dorsal fins that are rounded at the tips.

58-59 They have 12 to 15 rays on their dorsal fins, and 17 to 20 rays on their anal fins. Keeltail needlefish have gill-rakers, their caudal peduncles have lateral keels, with a lateral line running ventral to it, and grow up to 50 cm long Claro, R., 1994. Características generales de la ictiofauna. p. 55-70. In R. Claro (ed.) Ecología de los peces marinos de Cuba.

Elacatinus colini are born with a fully functional mouth, inflated swim bladder, pigmented eyes, and two visible otoliths. After about 18–20 days post hatch (dph), fin folds are completely gone, and the pelvic and dorsal fins begin to form. At around 20–28 dph, the pelvic fin elongates but remains unfused. Pre-settled larvae have elongated snouts, partially fused pelvic fins, and exhibit the first dorsal fin.

The rosy tetra has a light pink-white body with red fins, except the dorsal fin which can be black or white, and the caudal fin which is pink-white with two elliptical red spots on it. It has a faint black line from the top of its eyeball through the pupil, to the bottom of the eyeball. Like many other tetras, the males have longer dorsal fins than the females.

The hawkfishes are strictly tropical, perciform marine fishes of the family Cirrhitidae associated with the coral reefs of the western and eastern Atlantic and Indo-Pacific. They share many morphological features with the scorpionfish of the family Scorpaenidae. Black-sided hawkfish (Paracirrhites forsteri) from East Timor Hawkfishes have large heads with thick, somewhat elongated bodies. Their dorsal fins are merged, with the first consisting of 10 connected spines.

The anal fin is much smaller than the dorsal fins. The caudal fin is relatively short and broad, with an indistinct lower lobe and a ventral notch near the tip of the upper lobe. The skin is thick and covered by well-calcified dermal denticles. Extremely variable in coloration, the coral catshark lacks prominent saddle markings but rather has many black and white spots on a grayish background.

The white-tip catshark (Parmaturus albimarginatus) is a recently described, deepwater catshark, known only from a single specimen collected from northern New Caledonia, at a depth of 590–732 m. The only known specimen, an adult male, measured a total of 57.7 cm in length. These sharks have spiracles, which are respiratory openings behind the eyes. Catsharks, all in all, are likewise recognized by two little dorsal fins.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. armatus can be distinguished from other members of the genus Microsynodontis by examining the serrations on the pectoral fin spines. The leading edge of the spine is finely serrated, and the trailing edge is coarsely serrated.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. hirsuta can be distinguished from other members of the genus Microsynodontis by examining the dorsal spine, and the Tubercles on the head. The dorsal spine is straight, whereas all other species in the genus have gently curved spines.

The two similarly-sized dorsal fins are placed well back on the body. The anal fin is low and positioned just in front of the caudal fin. The caudal fin has only an upper lobe, which contains a prominent ventral notch near the tip and is angled almost horizontally relative to the body. Adult epaulette sharks are beige to brownish above with many widely spaced brown spots and subtle darker bands.

The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. ornatipinnis, the spine of the dorsal fin is about to times as long as the head, slightly curved, smooth in the front and serrated on the back.

The mandibular barbels have short and broad branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. marmoratus, the spine of the dorsal fin is short, about half the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

Folds of skin with a single triangular lobe are present on the sides of the head. The teeth are small, sharp, and of similar shape in both jaws. The pectoral and pelvic fins are wide with rounded tips; the two dorsal fins are positioned on the muscular tail behind the pelvic fins. The anal fin is absent, and the caudal fin has a larger lower lobe than upper.

Mackerel scad have 9 spines and 31–36 rays on their dorsal fins, while there are seven spines and 27–30 rays on their anal fins. The mackerel scad's fins are black metallic to blue-green and its belly is white. The edge of the operculum has a small, black spot,Smith-Vaniz, W.F., 1986. Carangidae. p. 638-661. In M.M. Smith and P.C. Heemstra (eds.) Smiths' sea fishes.

The two known Echinochimaera species lived in the Upper Mississippian (Serpukhovian). Fossils of the species were found in the Bear Gulch Limestone in Montana, United States. Both species have rounded bodies and paddle-like tails as well as large pectoral fins, two dorsal fins and a jaw fused to the braincase. The paddle-like tails indicate that E. meltoni was likely not a predator nor a fast swimmer.

It has a flattened pectoral fin disk about as wide as long, with rounded corners and straight anterior margins. There is a skirt-like nasal curtain in front of the mouth, without lateral lobes. The tail is short and stout, measuring 64-76% the length of the disk and bearing a serrated spine. The tail ends in a small caudal fin; there are no dorsal fins or lateral folds.

Sharks of the family Dalatiidae are small-sized to medium-sized, with two spineless dorsal fins. They are described as having strong jaws with dagger-like upper teeth and wider blade-like teeth in the lower jaw. From the one finding of the pocket shark in the Gulf of Mexico (M. mississippiensis), the mouth was described to have a rectangular-like opening on the underside of the body.

The mouth contains 14 upper and 16 lower tooth rows; each tooth has a single, slightly inward-curving cusp. There are five pairs of gill slits. The tail is short and robust, with a prominent "keel" of skin running along either side. There are two dorsal fins with nearly straight trailing margins; the first is tall with a pointed apex, while the second is much smaller with a rounded apex.

Usually two serrated stinging spines, with the upper generally larger than the lower, are present atop the tail about halfway along its length. The tail lacks dorsal fins and fin folds. The skin is completely smooth. The dorsal coloration ranges from yellowish to dark grayish brown, which is darkest toward the midline and lightest towards the fin margins; some larger individuals also gain a smattering of fine black and beige spots.

While swimming the dorsal fins are folded. When resting, T. delaisi lifts up the anterior part of the body and leans on the lower edge of the pectoral and on the ventral fins. T. delaisi sleeps on unprotected substrate relaying entirely on its camouflage.⁠ To scratch one of its sides, T. delaisi turns on that side and swims (using tailbeats for locomotion) to rub its body against the substrate.

Pempherus poeyi has a moderately deep, highly compressed body with an straight dorsal profile. It has relatively large eyes and a large oblique mouth. They have 4-5 spines and 8-9 soft rays in their dorsal fins while there are 3 spines, and 22-24 soft rays in the anal fin. They vary in colour from light yellowish brown, slightly duskier dorsally, to blackish on entire upper flanks and tail.

The broad, triangular pectoral fins originate at or slightly before the level of the fifth gill slit. There is no ridge between the first and second dorsal fins. The lower lobe of the caudal fin is half the length of the upper, which has a strong notch near the tip. The dermal denticles are small and overlapping, usually with 7 horizontal ridges, giving the skin a smooth feel.

M. productus California, Cordell Bank National Marine Sanctuary Its length is about 3 ft (90 cm) and it can live up to 20 years. Its coloration is metallic silver-gray with black speckling and pure silvery white on the belly. The North Pacific hake has two dorsal fins and a truncated caudal fin. Its pectoral fin tips usually reach to or beyond the origin of its anal fin.

The outer pair of mandibular barbels is about as long as the head, the inner pair is about as long. The mandibular barbels, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. resupinatus, the spine is as long as the head, slightly curved, smooth in the front and back.

The outer pair of mandibular barbels is a little under twice the length of the inner pair. They have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. soloni, the spine of the dorsal fin is a little shorter than the length of the head, smooth in the front and serrated on the back.

In common with other needlefish, this species has an elongate body with long, beak-like jaws filled with teeth. The dorsal and anal fins are positioned far back along the body close to the tail. The body is silvery-green, darker above and lighter below with a dark band running horizontally along the flank. Slight sexual dimorphism exists, the male fish often having anal and dorsal fins with a black edge.

In form, the apron ray resembles the genus Narcine in having a circular pectoral fin disc, two dorsal fins, and a stout tail with lateral folds. Its distinguishing feature is its pelvic fins, which are merged beneath the tail to form a continuous disc. The maximum length reported for the apron ray is a 54 cm male; the females attain maturity at 27.5 cm and the males at 35–46 cm.

Identification of individual sailfish based on the shape of their dorsal fins identified individual preferences for hitting to the right or left side. The strength of this side preference was positively correlated with capture success.Kurvers RHJM, Krause S, Viblanc PE, Herbert-Read JE, Zalansky P, Domenici P, Marras S, Steffensen JF, Wilson ADM, Couillaud P & Krause J (2017) "The evolution of lateralisation in group hunting sailfish". Current Biology.

Narcine is a genus of electric rays in the family Narcinidae. These species have a rounded pectoral fin disc and two dorsal fins, the first usually smaller than the second and placed behind the pelvic fin bases. The tail is longer than the disc and has a lateral fold. The spiracles are close behind the eyes, the nasal flaps are merged into a flap in front of the mouth.

The anterior margin of the organ is slightly rounded, while a duct like tubular process extends from the ventral surface to the urogenital opening. The species has pale sandy brown colour overall, with a slightly paler belly and slightly darker upper operculum. There are no dark blotches present on the side of the fish, while the first and second dorsal fins and caudal fin are dusted with black.

It has two separate dorsal fins, the first having 8 spines with the second having a single spine and 28 to 32 soft rays. The anal fin has 2 detached spines to its front followed by a single spine and 24 to 28 soft rays. The pectoral fins are as long or longer than the length of the head. The scales in the lateral line and large and form scutes.

It has two separate dorsal fins, the first having 8 spines with the second having a single spine and 28 to 35 soft rays. The anal fin has 2 detached spines to its front followed by a single spine and 24 to 30 soft rays. The pectoral fins are as long or longer than the length of the head. The scales in the lateral line and large and form scutes.

Typical bait for these traps include rotten cheese and dog food, or "stink bait", and old rotted shad work well. Catches of as many as 100 fish a day are common in catfish traps. An unusual method practiced in the Southeastern United States is noodling – catching catfish by hand. When removing the hook from a catfish, anglers should be mindful of the sharp spines on the pectoral and dorsal fins.

Steindachneridion species are large fish, reaching 100 cm (40 in) in total length or more. S. doceanum reaches 42 cm (17 in) in standard length. S. melanodermatum reaches a length of about 53.2 cm (21 in) SL. S. punctatum reaches about 70 cm (28 in) SL. These fish have relatively small eyes and heads. They have long maxillary barbels that extend to the base of their dorsal fins or adipose fins.

The anal fin consists of 2 detached spines anteriorly followed by 1 spine and 17 or 18 soft rays. Both the anal and dorsal fins are elongate, with the dorsal lobe being over twice the length of the head. The pectoral fin is falcate, and also longer than the head. The lateral line has a short, strong anterior arch, with 40 to 45 scutes on the straight posterior section.

There are over 80 tooth rows in the upper jaw. There are five pairs of gill slits; papillae (nipple-like structures) are present on the gill arches. The two dorsal fins are triangular with rounded apexes and gently concave trailing margins. The first dorsal fin is slightly larger than the second and originates behind the pectoral fin bases, while the second originates roughly above the rear of the anal fin base.

The rock goby is usually black with white blotches, but they can change color, and males are much more black when guarding the eggs. The neck area lacks scales and there is a pale band on the top of the first dorsal fin. Both dorsal fins lack black spots on their leading edges. This species can reach a length of TL and has been known to live for ten years.

The two dorsal fins bear long spines and have narrowly rounded apexes, concave posterior margins, and short free rear tips. The first dorsal fin originates above the pectoral fin insertions; the second is smaller than the first and originates behind the pelvic fins. The pectoral fins are medium- sized with rounded tips, the pelvic fins are small, and there is no anal fin. There are lateral keels on the caudal peduncle.

Chaenogobius annularis has a light brown head and body with six, or so, broad vertical bands along the body and with several small, dusky spots and a distinct blotch on the caudal peduncle. The dorsal fins are light brown with darker, sinuous horizontal bands while the caudal and pectoral fins are also light brown but are marked with darker vertical bands. It grows to a maximum total length of .

Upeneichthys vlamingii has a moderately long and compressed body with a rounded dorsal profile which is steep in front of first dorsal fin. It has a long snout and is small eyed with a small mouth which has fleshy lips which do not reach the front of the eye. It has two dorsal fins. The first is spiny and is taller and shorter base than the second which contains soft-rays.

The Squaliformes are an order of sharks that includes about 126 species in seven families. Members of the order have two dorsal fins, which usually possess spines, they usually have a sharp head, no anal fin or nictitating membrane, and five to seven gill slits. In most other respects, however, they are quite variable in form and size. Most species of the squaliform order live in a saltwater or brackish waters.

The blotchy swellshark, or Japanese swellshark, (Cephaloscyllium umbratile) is a common species of catshark, belonging to the family Scyliorhinidae. The Blotchy swellshark is found at depths of in the northwestern Pacific Ocean, from Japan to Taiwan. It is benthic in nature and favors rocky reefs. Reaching in length, this thick-bodied shark has a broad head, large mouth, and two unequally-sized dorsal fins positioned far back past the pelvic fins.

This particular species of weasel shark is slender with a moderately long snout, large eyes, and a short and small mouth. It has small, serrated upper teeth and erect-cusped lower teeth. It is identified by its light grey color and longitudinal yellow stripes on the sides of the body. Of its two dorsal fins, the first fin, located in front of the pelvic fins, is larger than the second.

Maximum sizes in aquaria tend to be slightly smaller than in the wild. Many Hemichromis species are brightly coloured, though brighter body colouration is generally evident during breeding. Sexual dimorphism is limited, though male jewel cichlids are typically more brightly coloured and in some species have more pointed anal, ventral and dorsal fins. In some species, such as Hemichromis cristatus, the females can have coloring as bright as the males.

The disparate angelshark (Squatina heteroptera) is a species of angelshark. It occurs at depths down to 164 m in the Gulf of Mexico and reaches a length of . Heteroptera in its name refers to the difference in size, shape and area of the two dorsal fins. Disparate angelsharks have the typical angel shark body form that is broadly flattened with large pectoral/pelvic fins and eyes and spiracles on the top of their heads.

Like all known members of the family Synanceiidae, all members of the genus Inimicus possess a complex and extremely potent venom. It is stored in glands at the bases of needle-like spines in their dorsal fins. Upon contact with the dorsal fin, the fish can deliver a very painful, potentially fatal, sting. The venom consists of a mixture of proteolytic enzymes, including stonustoxin (a hemotoxin), trachynilysin (a neurotoxin), and cardioleputin (a cardiotoxin).

The division occurs at a biogeographic barrier known as the Burdekin Gap. In their 1919 monograph of the family Atherinidae, David Starr Jordan and Carl Leavitt Hubbs maintained the two as separate species—P. signifer and P. signata—based on the number of rays in the dorsal fins and differences in the filaments of males. Gilbert Whitley examined material from the Low Isles off Cairns and maintained them as separate in 1935.

Toshimitsu and Watanabe decided to base Godzilla's design on dinosaurs and, by using dinosaur books and magazines as a reference, combined elements of a Tyrannosaurus, Iguanodon and the dorsal fins of a Stegosaurus. Despite wanting to have utilized stop motion animation, Tsuburaya reluctantly settled on suitmation. Toshimitsu sculpted three clay models on which the suit would be based. The first two were rejected but the third was approved by Tsuburaya, Tanaka, and Honda.

There is a prominent midline ridge along the back, which continues between the dorsal fins. The long, keel-like anal fin originates behind the second dorsal fin. The caudal fin is low and lacks a lower lobe; the upper lobe has a strong ventral notch near the tip. Adults are a plain tan color above and white below, sometimes with an orange tint on the fin margins; juveniles have faint lighter spots on the fins.

The hardnose shark (Carcharhinus macloti) is a species of requiem shark, in the family Carcharhinidae, so named because of the heavily calcified cartilages in its snout. A small bronze-coloured shark reaching a length of , it has a slender body and a long, pointed snout. Its two modestly sized dorsal fins have distinctively elongated rear tips. The hardnose shark is widely distributed in the western Indo-Pacific, from Kenya to southern China and northern Australia.

Smallmouth scad, Alepes apercna The species in Alepes are all relatively small fish, with the largest, A. vari, growing to . The other species are much more often encountered at sizes below . They have strongly compressed ovate to oblong shaped bodies, with fin arrangements much like the rest of the Carangidae. They have two dorsal fins, the first consisting of weak spines and the second of a single spine followed by a number of soft rays.

The mouth is small, with thick, fleshy lips; the teeth in the upper jaw are narrow, erect, and smooth-edged, while those in the lower jaw are broad, blade-like, and smooth-edged. Only one row of teeth in the lower jaw are functional. The large dorsal fins are subtriangular in shape, with the first dorsal spine sloping slightly backward. The pectoral fins have a convex front margin and a concave rear margin.

Oxynotus paradoxus is a rare shark found in the deep waters of the ocean from about 265–750 m below ocean level. At birth, O. paradoxus is about 25 cm in length and can grow up to 118 cm in length. It has a compressed body form with a blunt snout and a wide, flattened head. O. paradoxus has two tall, narrow and pointed dorsal fins that contain concave trailing edges, but no anal fin.

Greater amberjacks, Seriola dumerili, are the largest of the jacks. They usually have dark stripes extending from nose to in front of their dorsal fins. They have no scutes and soft dorsal bases less than twice the length of the anal fin bases. They are usually 18 kg (40 pounds) or less, and are found associated with rocky reefs, debris, and wrecks, typically in 20 to 75 m (10 to 40 fathoms).

The fire eel's base coloring is dark brown/grey, while the belly is generally a lighter shade of the same color. Several bright red lateral stripes and spots mark the body and vary in intensity depending on the age and condition of the individual. Usually, the markings are yellow/amber in juvenile fish, changing to a deep red in larger ones. Often the anal, pectoral, and dorsal fins have a red edging.

The five pairs of gill slits are large and increase in size from the first to the last. The two dorsal fins are rounded and lack spines; the first is smaller than the second and located about halfway between the pectoral and pelvic fins. The pectoral fins are enlarged into rounded paddles. The pelvic fins are small and originate at the level of the second dorsal fin; the anal fin is absent.

The brown bullhead grows to be approximately in length and is a darker brown-green dorsally, growing lighter green and yellow towards the ventral surface. The belly is off-white or cream, and the fish has no scales. Additionally, there are darker, brown-black speckles along the entire surface of the fish. The brown bullhead has two dorsal fins, a single adipose fin, abdominal pelvic fins, and an anal fin with 21 to 24 rays.

The five pairs of gill slits are minute. The small dorsal fins have rounded apices and are placed far back, on the last third of the body. The first dorsal fin originates slightly ahead of the pelvic fins, while the second dorsal originates closely behind and measures almost a third again the height of the first. The pectoral fins are small and rounded, and positioned relatively high on the body behind the fifth gill slit.

The first dorsal fin originates over the pectoral fin free rear tips, and the much smaller second dorsal fin originates over the last third of the anal fin base. The dorsal fins do not have a ridge between them. The lower lobe of the caudal fin is well-developed and the upper lobe has a ventral notch near the tip. This shark is plain gray, brown-gray, or purple-gray above, and white below.

Atheriniformes are generally elongated and silvery in colour, although exceptions do exist. They are typically small fish, with the largest being the jacksmelt, with a head-body length of , and the smallest species, such as the Bangkok minnow, being only in adult length. Members of the order usually have two dorsal fins, the first with flexible spines, and an anal fin with one spine at the front. The lateral line is typically weak or absent.

The outer pair of mandibular barbels has three simple branches, and the inner pair has five or six simple branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. courteti, the spine of the dorsal fin is about half the length of the head, smooth in the front. The remaining portion of the dorsal fin is made up of seven branching rays.

The shark is grey- brown with small, round black and white spots and a distinctive white neck spot. The bases and tips of the pectoral fins have symmetrical dark spots, as well as the base of the tail and the lower edge of the dorsal fins. Eyespots with white edges may be present. The outer edges of the dorsal and caudal fins are white, those of the thoracic and pelvic fins dark.

Teeth are absent on the vomer, the small bone in the roof of the mouth, and the tongue has two longitudinal ridges. A little tunny The snout is shorter than the rest of the head. The little tunny has a dorsal fin with 10 to 15 tall, descending spines, as well as a much smaller second dorsal fin followed by eight finlets. At the base, the two dorsal fins are separated by a small interspace.

Craterocephalus eyresii is a small drab yellowish-grey coloured fish with greenish-silvery underside, and a silver mid-lateral stripe which has some dark melanophores around it., and transparent to yellowish fins. There are two dorsal fins which are widely separated with the first dorsal fin originating before the tips of the ventral fins and the anal fin origin lies directly underneath the origin of second dorsal fin. The caudal fin isforked.

Augusto, Joana F., Frasier, Timothy R., and Whitehead, Hal. (2013). "Using photography to determine sex in pilot whales (Globicephala melas) is not possible: Males and females have similar dorsal fins". Marine Mammal Science, 29:213-220. However, males are bigger in size, and relative fin dimensions as well as other characteristics may still be discovered to allow for distinguishing the sex of at least certain age classes for free-ranging pilot whales.

After destroying part of Shibuya with shock waves generated by her beating wings, Megaguirus heads to the waterfront and faces Godzilla. As they engage in a lengthy battle, she uses her speed to avoid Godzilla's attacks, but Godzilla eventually uses his own speed against her. As she flies toward Godzilla, it lunges forward with its dorsal fins in her path. She flies into the fins, and one of her arms is severed.

Adult males possess alar spines (on the dorsal surface of the pectoral fins near the tips). The tail is slightly longer than the disc, bearing a single median row of 23-29 thorns and two similar-sized dorsal fins near the end without an interdorsal thorn. The caudal fin is long and tapering, with a filamentous fold on its upper surface. Its teeth number 34 in the upper jaw and 23 in the lower.

Pacific lamprey digging a nest (redd) Pacific lampreys passing through the Bonneville Dam Pacific lampreys grow to about as adults. They are anadromous and semelparous. They have slender, elongated bodies with two dorsal fins arising far back on the body. The anal fins are rudimentary and the lower lobe of the caudal fin is larger than the upper lobe and both lobes are continuous with the dorsal fin and the anal fin.

Over large distances the locomotion of T. delaisi can be described as anguilliform: The propulsion is caused by wavy movements of tail and body. During this motion the pectoral fins are adducted and the 3rd dorsal fin and the caudal fin are spread. Raising all dorsal fins precedes swimming over short distances. Repeated synchronous adduction of the pectoral fins thrusts the body forward and is aided by backwards- and downwards-movements of the pectoral fins.

The Raffles Bulletin of Zoology, 50(1): 215-226. This is a fairly elongated goby up to standard length. The background colour is whitish marked with five vertical brown or orange bars. It is most readily distinguished from its congeners by a row of red spots along the margin of both dorsal fins and the upper part of the caudal fin and also by a prominent black spot just above and behind the eye.

Synodontis schall has a shield on its body and has strong bony spines on the pectoral and dorsal fins. Some areas of new evolutionary forces have allowed for the Synodontis schall to have different phenotypes. Recent studies have found evidence for an increase number of teeth and gill rakers which could possibly point to a change from them being herbivores to carnivores. The swim bladder of Synodontis schall is whitish in appearance.

The outer pair of mandibular barbels is about to as long as the head, and the inner pair is as long as the head., both with long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. smiti, the spine is a little shorter than the head, slightly curved, smooth in the front and serrated on the back.

The exact purpose of the skin folds is not known, but is a characteristic of the species of Syndontis that are endemic to Lake Tanganyika. External papilla are present but do not extend onto the fins. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. tanganyicae, the spine of the dorsal fin is long, nearly straight, and ends with short, dark filament.

The colour of the body is a blue to green blue above and silver below, with young specimens having dark vertical cross bars. The operculum has a diffuse dark blotch .The spinous and soft dorsal fins, anal fins and caudal fin are a dusky yellow green. The anterior of the soft dorsal and anal fins have white tips and the pelvic fin is a white to grey colour, while the pectoral is hyaline.

Houndsharks, the Triakidae, are a family of ground sharks, consisting of about 40 species in nine genera. In some classifications, the family is split into two subfamilies, with Mustelus, Scylliogaleus, and Triakis in the subfamily Triakinae, and the remaining genera in the subfamily Galeorhininae. Houndsharks are distinguished by possessing two large, spineless dorsal fins, an anal fin, and oval eyes with nictitating eyelids. They are small to medium in size, ranging from in adult length.

Two dorsal fins are present, with the first more than twice the size of the second and positioned opposite the large pelvic fins. The tail is short and stocky, terminating in a large, triangular caudal fin with a nearly straight trailing margin. This ray is dark gray, slate, or brown above, sometimes with small darker spots that increase in number with age; the underside is white. Males attain a maximum known length of , and females .

A pair of Antarctic minke whales showing their prominent, falcate dorsal fins Yushin Maru, showing the coloration of the baleen. Like their close relative the common minke, the Antarctic minke whale is robust for its genus. They have a narrow, pointed, triangular rostrum with a low splashguard. Their prominent, upright, falcate dorsal fin – often more curved and pointed than in common minkes –is set about two-thirds the way along the back.

Groundsharks, like this blacknose shark, have a nictitating membrane which can be drawn over the eye to protect it. Carcharhiniformes, the ground sharks, with over 270 species, are the largest order of sharks. They include a number of common types, such as catsharks, swellsharks, and the sandbar shark. Members of this order are characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin, and five gill slits.

The mullets or grey mullets are a family (Mugilidae) of ray-finned fish found worldwide in coastal temperate and tropical waters, and some species in fresh water. Mullets have served as an important source of food in Mediterranean Europe since Roman times. The family includes about 78 species in 20 genera. Mullets are distinguished by the presence of two separate dorsal fins, small triangular mouths, and the absence of a lateral line organ.

The mouth is on the ventral surface and is slightly arched, followed by the five pairs of small gill slits. Tail is as long as body, and has two well separated dorsal fins near its end, usually with two spines between them. The colouring of the dorsal surface varies from light brown to citrine or grey, with darker waved bands and numerous small white patches. Snout and margins are frequently clearer with dark spots.

Upeneus mascareinsis has dorsal fins which have a total of 8 spines and 9 soft rays. The pectoral fins have 15-16 soft rays. The gill raker counts are 7-8 + 19-22. There are 35-38 scales in the lateral line. The body has a depth of 22-26% of the standard length at the base of the origin of the dorsal fin and of 18-22% of the standard length it the anus.

Fins were considered abnormal if they displayed collapse, partial collapse, or bends. This is a higher prevalence of these deformities than in other areas of the world, as studies have reported rates of abnormal fins in wild adult males at 4.7% in British Columbia and 0.57% in Norway. Researchers in 1994 found that of the ~300 killer whales photographed off the coast of British Columbia, fewer than 1% were observed to have "droopy" dorsal fins.

Side view of M. birostris Manta rays have broad heads, triangular pectoral fins, and horn-shaped cephalic fins located on either side of their mouths. They have horizontally flattened bodies with eyes on the sides of their heads behind the cephalic fins, and gill slits on their ventral surfaces. Their tails lack skeletal support and are shorter than their disc-like bodies. The dorsal fins are small and at the base of the tail.

The sand goby has two dorsal fins with a wider gap between them than the common goby (Pomatoschistus microps), the anterior one consisting of six soft spines and the posterior one eight to eleven soft rays. The pelvic fins are fused with the anal fins. There are 58 to 72 scales along the lateral line and these scales are rather smaller than those of the common goby. The caudal fin is rounded.

The origin of the first and second dorsal fins lie over the rear of the pelvic fins and anal fin respectively. The pectoral fins are small and broad, with rounded corners. The pelvic fins are long and low; adult males have slender claspers and a slight "apron" formed from the fusion of the pelvic fin inner margins. The anal fin is elongated, its base measuring roughly a tenth of the total length, and rather angular.

Anal and dorsal fins are moderately long with short fin bases, usually roughly equal. Fins generally rounded, with the pelvic fins at the mid point of the body and the pectoral fins paddle shaped and low on the body. The caudal fin is relatively short. The body of the Shaw galaxias is mainly grey-brown to grey-tan on the upper surfaces and the sides above the lateral line and over the head and snout.

Daggertooths are similar in appearance to the related lancetfishes and barracudina. They are elongate, silvery, predatory marine fishes that lack scales and have sharp teeth likely used for hunting fishes. However, as their scientific name (meaning "without fins on its back") suggests, they lack dorsal fins which easily differentiates them from their close allies, especially the similar looking lancetfishes. Another feature that distinguishes daggertooths from lancetfishes are the placement of the large, fang-like teeth.

The Western criteria for lionchus combine the traditional characteristic side-view profiles of the ranchu and the lionhead.“The Diversity of Goldfish Varieties” an article from the Fish Tank Guide Website, a Lionchu description, date retrieved: 22 May 2007 The ranchu's deep body, broad and curved back, and tail placement has been merged with the large headgrowth of the lionhead. Lionchus do not have dorsal fins, a trait inherited from both parent breeds.

The five pairs of gill slits are long and placed on the sides of the head. The pectoral fins are angular, with the anterior lobes of their bases free from the head, and their outer tips forming an angle of slightly under 120°. The tips of the pelvic fins are rounded; males have thick claspers. The two dorsal fins are close in shape and size, with rounded to angular apexes and slightly convex trailing margins.

These are popular game and food fish. Dating from the upper Cretaceous, the centropomids are of typical percoid shape, distinguished by having two-part dorsal fins, a lateral line that extends onto the tail, and frequently, a concave shape to the head. They range from in length and are found in tropical and subtropical waters. The snook species range in maximum length from about , with maximum recorded weights of 1.0 – 26 kg (2.2 – 57 lb).

The vertebral count of this species is between 63 and 65 vertebrae. The caudal peduncle and the pelvic fins are short, with the pelvic fin not reaching past the pectoral fins. The dorsum is a marbled greenish-brown, sometimes reddish-brown on the most upper part, lightening on the flanks and underside. A distinct white edge is seen on the anal and dorsal fins and they have a dark spot at their posterior end.

The family can be divided into two groups, a temperate Eurasian clade and a more diverse subtropical/tropical South and Southeast Asian clade. These catfish do not have spines before their dorsal fins or adipose fins, and their pelvic fins are either small or absent. The anal fin base is usually very long. The largest species in this family is Silurus glanis, the Wels catfish, which can grow to lengths over and weigh over .

The bramble shark (Echinorhinus brucus) is one of the two species of sharks in the family Echinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. This rarely encountered shark swims close to the bottom of the seafloor, typically at depths of , though it may enter much shallower water. The bramble shark has a stout body with two small dorsal fins positioned far back and no anal fin.

There are 20–26 upper and 22–26 lower tooth rows; each tooth is knife-like, with a single main cusp and up to three cusplets on either side. There are five pairs of gill slits, with the fifth pair the longest. The pectoral fins are short and angular, while the pelvic fins are long and relatively large. The dorsal fins are small, with the first dorsal fin origin lying behind the pelvic fin origins.

The bighead spurdog (Squalus bucephalus) is a rare and little-known species of dogfish shark in the family Squalidae. It is found in deep water south of New Caledonia, and over the Norfolk Ridge. Reaching at least in length, this stocky shark is brown above and light below, with a broad head and two dorsal fins with long spines. It is the only member of its genus with both one- and three-pointed dermal denticles.

The lower jaw has three protruding lobes that fit into corresponding depressions in the upper jaw. There are around 47 upper and 50 lower tooth rows arranged in winding bands; the teeth are low and blunt with ridges on the crown. The five pairs of ventral gill slits are positioned close to the lateral margins of the head. The body is deepest in front of the two tall and falcate (sickle-shaped) dorsal fins.

Brachaelurus (blind sharks) is the sole genus of sharks in the family Brachaeluridae in the order Orectolobiformes. Only two species of blind sharks occur, both of which are native to shallow coastal waters up to deep, off the eastern coast of Australia. They are distinguished by the presence of long barbels, large spiracles, and a groove around the nostrils. They have two dorsal fins, placed close together on the back, and a relatively short tail.

Its head is wide, flattened, and blunt, with small eyes on top and a pair of long barbels underneath. It has large pectoral fins, two nearly equal-sized dorsal fins placed far back on the body, and an anal fin placed close to the caudal fin. The blind shark feeds primarily on small invertebrates and bony fishes. It is aplacental viviparous with females bearing litters of 7-8 pups in the summer.

White crappies are morphologically similar to black crappies. They have 5–10 dark vertical bars along their bodies, rather than the randomly scattered spots like the black crappie. The white crappie has a silvery color with green or brown shades along its back, with dark lateral bars along its side, and a white belly. The dorsal fins of the white crappie starts farther back on the body than those of the black crappie.

There are 68-76 pored scales in the simple lateral line which extends from upper end of gill opening to the middle of the caudal fin fork. The upper sides of its head and body tinged with gold, this changes to silver on the lower flanks. The margins of both dorsal fins and the caudal fins are black, the rest of these fins are blackish while pelvic and anal fins are white. The pectoral fin is yellow with melanophores.

Its colour fades to silvery white on the posterior portion of the belly. It has two dorsal fins, the first of which has a tiny spine at the front with the second and third spines being much longer. The anal fin lies directly below the posterior dorsal fin. The colour of the fins is pinkish-orange and larger fish have a line of brown spots on the membranes of second dorsal fin and the anal fin.

A male midnight molly An entirely melanistic form exists called the midnight molly, or nondescriptly, "black molly". The latter originally refers to melanistic breeds of Poecilia sphenops. Midnight mollies actually originated from hybrids between that and the present species. As hybridization, like in most Poecilia, is easy between these two species and due to the more spectacular appearance of P. latipinna, such sailfin-black molly hybrids, with males' conspicuous, large, yellow-rimmed dorsal fins, are often seen.

Coloration can also vary within one species, making it difficult to differentiate between them. Rather than typical dorsal fins, the front-most of the three fins is called the illicium or "rod" and is topped with the esca or "lure". The illicium often has striped markings, while the esca takes a different form in each species. Because of the variety of colours even within a single species, the esca and illicium are useful tools to differentiate among different varieties.

The boundary between the darker cape and coloration on the flanks is often faint or diffuse. Both the mask and dorsal cape are often only visible in good lighting conditions. Compared to females, adult males have more rounded heads, longer flippers, taller dorsal fins, broader tail flukes and some have a pronounced ventral keel posterior to the anus. Melon-headed whales grow up to in length, and weigh up to , adult males being slightly larger than females.

Electric rays have a rounded pectoral disc with two moderately large rounded-angular (not pointed or hooked) dorsal fins (reduced in some Narcinidae), and a stout muscular tail with a well-developed caudal fin. The body is thick and flabby, with soft loose skin with no dermal denticles or thorns. A pair of kidney-shaped electric organs are at the base of the pectoral fins. The snout is broad, large in the Narcinidae, but reduced in all other families.

The finless sleeper ray can be identified by its lack of dorsal fins. The pectoral fin disc of the finless sleeper ray is oval in shape; it is slightly wider than long in adults, and circular or longer than wide in juveniles. The small and bulging eyes are immediately followed by smooth-rimmed spiracles of roughly equal size. A pair of kidney-shaped electric organs are visible beneath the skin on either side of the head.

An alternate common name for this species is Knopp's shark, originally used by Florida fishery workers since before the species was described. Phylogenetic studies published by Jack Garrick in 1982 and Leonard Compagno in 1988, based on morphology, placed the bignose shark in the "obscurus group" of Carcharhinus, centered on the dusky shark (C. obscurus) and the Galapagos shark (C. galapagensis). The group consists of large, triangular-toothed sharks with a ridge between the dorsal fins.

Both dorsal fins have very long free rear tips, and there is a subtle midline ridge between them. A prominent notch is present on the caudal peduncle at the dorsal origin of the caudal fin. The caudal fin has a well-developed lower lobe and a longer upper lobe with a ventral notch near the tip. The skin is covered by overlapping, oval-shaped dermal denticles; each denticle has three horizontal ridges leading to marginal teeth.

The first dorsal fin is fairly large and triangular, with a blunt apex sloping down to a sinuous trailing margin; its origin lies over the free rear tips of the pectoral fins. The second dorsal fin is small and low, and originates over the middle of the anal fin base. There is no ridge between the dorsal fins. The caudal peduncle bears a deep, crescent- shaped pit at the origin of the upper caudal fin lobe.

Parioglossus galzini is a species of dartfish presently known only from the island of Rapa Iti, French Polynesia. This tiny fish (up to SL) is found on substrates of mud and rubble in shallow inshore waters of less than in depth. It can be distinguished from its congeners in several ways, most notably by the complete absence of a dark lateral stripe and the presence of a membrane linking the two dorsal fins in both sexes.

Blackeye gobies range in color from creamy white to a mottled dark purple-brown, but can easily be recognized by the distinctive black spot on their first dorsal fins and an iridescent blue spot beneath their eyes. They are capable of rapidly changing their color in response to social situations or threats. They are also protogynous hermaphrodites, starting out in life as females. They are highly territorial and each male usually maintains a harem of two to eight females.

Chelon possesses the elongated body and dorsal fins typical of the order Mugiliformes, with frontal fins defined by four spines and anal fins with soft rays. The maximum sizes described vary between 15 cm for the Cape Verde mullet and 32 cm for the thicklip grey mullet.Thomson, J.M., 1990. "Mugilidae". p. 855-859. In J.C. Quero, J.C. Hureau, C. Karrer, A. Post & L. Saldanha (eds.) Check-list of the fishes of the eastern tropical Atlantic (CLOFETA).

The pectoral fins have straight leading margins and rounded outer corners, that form an angle slightly over 120°. The anterior lobes of the pectoral fins are free from the head. The pelvic fins are roughly triangular and about three-quarters as long as the pectoral fins; the pelvic fin rear tips are approximately even with the origin of the first dorsal fin. The two dorsal fins are similar in shape, with the first slightly larger than the second.

A slender, black shark reaching in length, the viper dogfish can be recognized by its narrow, triangular jaws and well-spaced, fang-like teeth. It also has two spined dorsal fins, dermal denticles with faceted crowns, and numerous light-emitting photophores concentrated on its ventral surface. Feeding mainly on bony fishes, the viper dogfish captures prey by protruding its jaws and impaling them with its teeth. Its impressive gape allows it to swallow relatively large fish whole.

Amblyopinae is a subfamily of elongated mud-dwelling gobies commonly called eel gobies or worm gobies; it has been regarded as a subfamily of the family Gobiidae, while the 5th edition Fishes of the World classifies it as a subfamily of the family Oxudercidae. The members in the subfamily have two dorsal fins that are connected by a membranous structure and their eyes are highly reduced in size. They are usually pink, red, or purple in coloration.

Both dorsal fins are immediately preceded by stout, grooved spines, with the second much longer than the first. The small first dorsal fin has a rounded apex and a nearly straight trailing margin, with its origin lying behind the pectoral fins. The second dorsal fin is rather angular and has about double the area of the first, with its origin located opposite the midpoint of the pelvic fin bases. The pectoral fins are small and rounded.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. emarginata can be distinguished from other members of the genus Microsynodontis by examining the caudal fin. The fin is slightly forked or lobed, whereas all other members of the genus have caudal fins that are either rounded on the trailing edge or with a straight trailing edge.

The outer pair of mandibular barbels is longer than the inner pair, and is about the length of the head. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. caudalis, the spine of the dorsal fin is short, about the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. geledensis, the spine is as long as the head, nearly straight, serrated in the front and smooth on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

Goatfishes are characterized by a pair of chin barbels (or "goatee"), which contain chemosensory organs and are used to probe the sand or holes in the reef for food. Their bodies are deep and elongated, with forked tails and widely separated dorsal fins. The first dorsal fin has 6-8 spines; the second dorsal has one spine and 8-9 soft rays, shorter than anal fin. Spines in anal fin 1 or 2, with 5-8 soft rays.

The species' tail is extremely long and slender for a skate and is completely absent of dorsal fins; these factors make the species easily distinguishable from other skate species in the area. It has a large number of denticles on its dorsal disc, completely covering it. Male specimens have thorns on their anterior disk as adults and females have them in the middle of their tail and disc. In addition, males adults have claspers, which are thin and long.

The giant gourami is an egg layer, and the male will build a bubble nest before spawning. The male and female are distinguished by the dorsal fins and body color. The dorsal fin on the male ends in a point, and the body is darker changing to nearly black during spawning. When breeding, the water in the tank should be decreased to about 20 cm (8 in) deep and the temperature should be 28 °C (82 °F).

The red velvetfish (Gnathanacanthus goetzeei) is a marine scorpaeniform fish of the inshore waters of western and southern Australia. It is the sole member of the family Gnathanacanthidae and genus Gnathanacanthus. This fish is red all over, and instead of scales, its skin is covered with small tubercles, hence its name. All of its fins (except caudal) are large and spined, and of its two dorsal fins, the forward one reaches to just above the large eyes.

Two small, closely spaced dorsal fins are located near the tip of the tail. Adults have small dermal denticles and usually no midline thorns, though there are strong spines on the dorsal surfaces of the head, shoulders, and tail. Males tend to have fewer spines than females. The coloration of the little skate ranges from grayish to uniform or variable shades of brown above, becoming lighter towards the edges of the disk, and white or gray below.

The pectoral fins are rather long and broad. The first dorsal fin originates over the rear of the pelvic fin bases; the second dorsal fin is slightly larger and originates over the rear of the anal fin base. The pelvic and anal fins are long and low, and larger than the dorsal fins. The free rear tips of the pelvic fins may be fused together to some degree, but never completely; males have slender, pointed claspers.

Urotrygonidae is a family of rays in the order Myliobatiformes, commonly referred to as the American round stingrays or round rays. They are native to the tropical and warm temperate marine waters of the Americas. The two genera in this family were formerly placed within the family Urolophidae, whose species are now restricted to the Indo-Pacific. They have a round pectoral fin disk, a slender tail with a caudal fin, no dorsal fins, and a venomous tail spine.

The grey gurnard has a large head but does not have a deep occipital groove. There are two dorsal fins, the first has 7–10 spines and the second has 18–20 rays. The anal fin has 17–20 rays, the pectoral fins are short, kust extending as far as the anal fin origin. The scales along the lateral line are skightly larger than the scales covering the body, and have a spiny keel and a toothed rear edge.

The two dorsal fins have rounded apexes and are placed close together; the base of each fin measures about two-thirds its height. The rear of the first dorsal fin base is located behind the rear of the pelvic fin bases. The second dorsal fin is only slightly smaller than the first. The short, robust tail has skin folds running along either side, and terminates in a large caudal fin shaped like a triangle with blunt corners.

The wide stingaree (Urolophus expansus) is a little-known species of stingray in the family Urolophidae, found off southwestern Australia. It typically occurs over sand in water deep around the edge of the continental shelf. This species has a broad diamond-shaped pectoral fin disc, a slightly pointed snout, and a tail with a leaf-like caudal fin, skin folds along either side, and no dorsal fins. Between its nostrils is a skirt-shaped curtain of skin.

External granular papilla are present. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. dhonti, the spine of the dorsal fin is long, about as long as the head, is almost completely straight, is smooth on the front and serrated on the back, and ends with short, dark filaments. The remaining portion of the dorsal fin is made up of seven dark branching rays.

The outer pair of mandibular barbels has long, simple branches, and the inner pair has short and thick branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. fuelleborni, the spine of the dorsal fin is slightly shorter than the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The preoperculum is hooked and has four spines, on pointing forwards and the remaining three point backwards. There are two high dorsal fins, taller in males than in females, and the first dorsal fin in males is a little higher than the second dorsal fin. The first dorsal fin has four rays and the second has 9-10 rays. The anal fin is similar in size to the second dorsal fin and it has a long tail.

The territory holder warns the intruder by raising its first dorsal fin. This gesture is succeeded by slowly moving the anterior part of the body up and down (further called rearing up) if the intruder does not retreat. The intruding male may respond with a rearing-up-motion itself. This initialises a fight: The territory holder, tail-beating and all dorsal fins spread, swims towards the intruder, where they move into either a parallel or an antiparallel position.

External papilla are present on the head, but not the body. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. irsacae, the spine of the dorsal fin is short, about as long as the head, slightly curved, rough on the front and serrated on the back, and ends with short, dark filament. The remaining portion of the dorsal fin is made up of seven branching rays.

The teeth are sexually dimorphic; those of adult males are spear-shaped with long, sharp cusps, while those of females and juveniles are plate-like with short posterior cusps. The pelvic fins are deeply incised, with the anterior lobe moderately long and slender and the posterior lobe broadly rounded. The tail is narrow, tapering gradually to a very slender tip and bearing two small dorsal fins near the end. The caudal fin is reduced to minute lobes.

The mandibular barbels have long, slender branches, and the outer pair is about as long as the inner pair. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. woosnami, the spine of the dorsal fin is about the length of the head, slightly curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The coachwhip trevally is a dusky olive green colour above, fading to a silvery white or yellow below with small blue to black blotches present on the dorsal line between the bases of the second dorsal fin rays. The upper caudal and soft dorsal fins are dusky blue, while the anal fin is yellow having white lobe tips. The pelvic and pectoral fins are yellow. There is a diffuse dark opercular blotch, which may be absent altogether.

The gulper shark (Centrophorus granulosus) is a long and slender dogfish usually about three feet in length generally found in deep, murky waters all around the world. It is a light grayish brown, paler ventrally, with a long snout and large greenish eyes. This deep water shark has two dorsal fins with long, grooved spines and the second dorsal fin smaller than the first. Its upper teeth are blade-like and lower have finely serrated edges.

Macroramphosus, snipefishes or bellowfishes, is a genus of fishes found in tropical and subtropical oceans at depths down to . According to FishBase, they are part of the family Centriscidae, but Nelson (2016) split that family, in which case the genus Macroramphosus is in the family Macroramphosidae. They have long second spines on their dorsal fins and tiny mouths at the tip of their greatly elongated snouts. The bodies of snipefish are more streamlined than in the related bellowfishes.

They have a steep upper profile with the antedorsal distance being larger than anteanal distance. At 16 mm (0.6 in) to 34 mm (1.3 in), juveniles have dark transverse bands on the trunk and the posterior part of their pectoral and dorsal fins are dark. At this length and smaller, the pectoral fins are largely transparent with light gray pigmentation in the anterior and posterior parts. The ventral fins are dark on juveniles smaller than 57 mm (2.2 in).

The dwarf sawfish has a torpedo-shaped body that resembles that of a shark, and grows to a length of about . It has broad, triangular pectoral fins and large, upright dorsal fins. The first dorsal fin is located directly above, or slightly behind, the origins of the pelvic fins, and the caudal fin has a very small lower lobe. The snout is broad and flat and is elongated into a rostrum with around twenty pairs of rostral teeth.

The body is grey to grey-brown dorsally and off-white on the belly. The juveniles (young sharks) usually have dark spots on the upper two thirds of the body. The first and second dorsal fins are of similar size and the caudal fin is asymmetric. Once believed to be a man-eater it is now known that this shark rarely attacks humans and if it does it is only in defense; or if it is baited.

The second dorsal and tail fins have many small dark spots that form wavy rows. E. microperca also has a distinct teardrop-shaped spot under the eyes and often several other dark lines radiating outward from the eyes on their heads and snouts. The breeding males have a band of red spots in the middle of their first dorsal fins. Males also have oversized pelvic fins, and their pectoral, pelvic, and anal fins are flushed with orange or red.

Some sharks can be induced into tonic immobility by inverting them and restraining them by hand, e.g. dogfish sharks, lemon sharks, whitetip reef sharks. For tiger sharks (measuring 3–4 metres in length), tonic immobility can be induced by humans placing their hands lightly on the sides of the animal's snout in the area surrounding the eyes. During tonic immobility in sharks, the dorsal fins straighten, and both breathing and muscle contractions become more steady and relaxed.

The chameleon goby can reach total length. It is pale greyish-brown with a white-speckled head and two longitudinal black bands extending along the flank from the head to the caudal peduncle. The two dorsal fins may be speckled with white and have a brown longitudinal stripe, and the anal fin an orange or grey band across the centre. Under certain circumstances, this fish can darken in colour so that the black bands are nearly invisible.

Synanceia is edible to humans if properly prepared. The protein-based venom quickly breaks down when heated, and raw stonefish served as part of sashimi is rendered harmless simply by removing the dorsal fins which are the main source of venom. The fish are considered a delicacy in many parts of Asia, including south Japan, south Fujian, Guangdong in China, and Hong Kong. In the Hokkien-speaking area, they are considered delicacies and good for health.

Retrieved on August 24, 2009. This species favors still, murky waters and is most common in bays, estuaries, and lagoons, and over sandy flats and outer reefs. Sometimes, an individual may venture into open water; one was filmed in the 1971 documentary Blue Water, White Death, in the vicinity of a sperm whale (Physeter macrocephalus) carcass. Juvenile sicklefin lemon sharks are often found on reef flats or around mangroves, in water so shallow that their dorsal fins are exposed.

Pentacerotidae or armourheads are a small family of fishes in the order Perciformes. They are native to the Indian Ocean, western and central Pacific, and southwestern Atlantic. They are generally found at rocky reefs below normal scuba diving depths, although several species occur in low densities at shallower depths. Their name, from Greek pente meaning "five" and keras meaning "horn", refers to the prominent, sharp spines in their dorsal fins (though these do not number five in all species).

There are 3 to 5 rows of sharp teeth in the upper jaw and 1 or 2 rows in the lower jaw. The eye is large and bulbous, giving the fish its alternative name of onion-eye grenadier. There are two dorsal fins, the front one having 11 to 13 finrays and the hind one running along the back to the tip of the tail. The anal fin is similarly long and narrow and there is no tailfin.

Upeneus moluccensis has an elongated body which has a sub-cylindrical anterior portion which becomes compressed towards the tail with two dorsal fins which are well separated, with the second dorsal fin directly above the anal fin. The caudal fin is deeply forked. The chin bears a pair of barbels which do not extend past the margin of the preoperculum. The upper and lower jaws, the palatine and the vomer are covered in brush-like or villiform teeth.

The pelvic fins are rounded and almost as large as the pectoral fins. The anal fin is less than half the size of the dorsal fins and is positioned very close to the base of the long, low caudal fin. The caudal fin comprises about a quarter of the total length, with no ventral lobe and a strong ventral notch near the tip of the upper lobe. The dermal denticles are large, giving the skin a rough texture.

They have jaws armed with bands of fine, pointed teeth. The cheek and operculum have lines of papillae which are also found around the preopercular margin and on each side of snout to above the eye. There are 3-5 large pores on the preopercular margin. It has two dorsal fins, the first, anterior dorsal fin, is rounded and has notches between its six spines and the second, posterior dorsal fin, is taller and slightly longer.

The teeth are numerous and small with multiple cusps; the upper teeth are exposed when the mouth is closed. The large, oval eyes are placed somewhat on the upper surface of the head, and have rudimentary nictitating membranes (protective third eyelids) and ridges underneath. There are two dorsal fins, the first much larger than the second. The first dorsal originates over the forward half of the pelvic fin bases, while the second is located over the anal fin.

Both sexes display by spreading their pectoral and caudal fins, and moving around or by the side of the other sex. Males will sometimes also spread their dorsal fins, repeatedly open and close their mouths, and position themselves on top of the females and rub their abdomens with their bodies. If a female accepts a male for spawning, they form a pair. Occasionally, another male might intrude upon the pair as they are mating and attempt to sneak fertilizations with the female.

The topsmelt silverside is a small, slim fish with a dorsally flattened body which can grow up to a total length of . It has two separate dorsal fins on its bright green back which contrasts with the silver to pale flanks and silvery underside. This species has a pointed head with small eyes and a rather rounded, blunt snout and an oblique mouth situated terminally with extendible jaws each equipped with a row of tiny forked teeth. Their gills are a golden-yellow.

The rear joint of the mouth extends past the level of rear margin of the adipose eyelid. The rear margin of the gill cover is serrated. They have two dorsal fins with the first dorsal fin having 8 spines and the second dorsal fin has a single spine and 11 to 13 soft rays while the anal fin has 3 spines and 10 to 15 soft rays. The base of the anal fin is shorter than the length of the head.

Profile view of a velvet belly lanternshark, from Les Poissons (1877). The velvet belly was originally described as Squalus spinax by Swedish natural historian Carl Linnaeus, known as the "father of taxonomy", in the 1758 tenth edition of Systema Naturae. He did not designate a type specimen; the specific epithet spinax is in reference to the spiny dorsal fins. This species was later moved to the genus Etmopterus via the synonymy of Constantine Samuel Rafinesque's Etmopterus aculeatus with Squalus spinax.

The lower teeth are much larger, with a strongly slanted, blade-like cusp at the top and interlocking bases. The five pairs of gill slits are tiny, comparable in size to the spiracles. Both dorsal fins bear stout, grooved spines at the front, with the second much longer than the first and curved. The first dorsal fin originates behind the short and rounded pectoral fins; the second dorsal fin is twice the size of the first and originates behind the pelvic fins.

The twohorn sculpin is typically 5–12 cm long and may reach 15 cm. It has a thin caudal peduncle, one sharp spine located in front of each eye and two spines behind, hence its common name. Like other sculpins, this species has two dorsal fins (the first is spiny while the second is soft-rayed), large pectoral fins and slender pelvics. The caudal fin is slightly rounded and has dark, vertical bars and a black spot at the base.

The slender bamboo shark, Chiloscyllium indicum, is a bamboo shark in the family Hemiscylliidae found in the Indo-West Pacific Oceans between latitudes 40° N and 10° S, and longitude 65° E and 160° E. Its length is up to 65 cm. Features: Mouth located in front of the eyes; Elongated slender precaudal tail; the shark has a brownish body with a number of dark spots and dashes. The dorsal fins are round, same size, and smaller than the pelvic fin.Compagno, Leonard.

The first dorsal fin is high and broad, with a pointed apex and a concave trailing margin; its origin lies roughly over the insertion (the rear of the fin base) of the pectoral fins. The second dorsal fin is relatively large and located about opposite the anal fin, which is about of equal size. There is no ridge between the dorsal fins. The caudal fin has a well-developed lower lobe and a ventral notch near the tip of the upper lobe.

The Portuguese dogfish (Centroscymnus coelolepis) or Portuguese shark, is a species of sleeper shark of the family Somniosidae. This globally distributed species has been reported down to a depth of , making it the deepest-living shark known. It inhabits lower continental slopes and abyssal plains, usually staying near the bottom. Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species (such as the kitefin shark, Dalatias licha) by the small spines in front of its dorsal fins.

The second dorsal fin is half again as tall as the first and bears a longer, curved spine. The pectoral fins are rounded at the tips, with the distance between them and the medium-sized, angular pelvic fins about equal to the distance between the dorsal fins. The anal fin is absent. The caudal peduncle is narrow, leading to a caudal fin with a well-developed lower lobe and a broad upper lobe with a ventral notch near the tip.

This can result in having their front facing teeth being covered in barnacles after many years. Baird's and Arnoux's also have similarly shaped small flippers with rounded tips, and small dorsal fins that sit far back on their body. Adult males and females of both species pick up numerous white linear scars all over the body as they age, and may be a rough indicator of age. These traits are similar in both sexes as there is little sexual dimorphism in either species.

Elasmobranchii is one of the two subclasses of cartilaginous fish in the class Chondrichthyes, the other being Holocephali (chimaeras). Members of the elasmobranchii subclass have no swim bladders, five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins, and small placoid scales. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. Extant elasmobranchs exhibit several archetypal jaw suspensions: amphistyly, orbitostyly, hyostyly, and euhyostyly.

The blacktip shark (Carcharhinus limbatus) is a species of requiem shark, and part of the family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean isolated and distinct from those in the rest of its range. The blacktip shark has a stout, fusiform body with a pointed snout, long gill slits, and no ridge between the dorsal fins.

The coral catshark (Atelomycterus marmoratus) is a species of catshark, and part of the family Scyliorhinidae. It is common on shallow coral reefs across the Indo-West Pacific, from Pakistan to New Guinea. Reaching up to in length, the coral catshark has an extremely slender body, a short head and tail, and two dorsal fins that are angled backwards. It can be identified by the numerous black and white spots on its back, sides, and fins, which often merge to form horizontal bars.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. laevigata can be distinguished from other members of the genus Microsynodontis by examining the pectoral spine, the shape of the caudal fin, and the length of the adipose fin. When viewed from above, the spines on the front edge of the pectoral spines are smooth, instead of serrated.

Rhizodonts' trunk was elongated, with pelvic, two dorsal and anal fins much reduced and placed posteriorly The anal and second dorsal fins formed a functional part of the tail. The lateral line system was elaborated on the skull and pectoral girdle - in Strepsodus the main trunk lateral line also had several subsidiary lines running parallel to it. This probably helped rhizodonts detect prey in the turbid, swampy environments where they lived. Rhizodont pelvic fins are known only from external morphology.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is about twice as long as the inner pair. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. budgetti, the spine of the dorsal fin is long and slightly curved, about as long as the head, bearing a long filament, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is about times as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. clarias, the spine is as long or slightly longer than the head, curved, and serrated on both sides. The remaining portion of the dorsal fin is made up of seven branching rays, terminating in a short filament.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have long, slender branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. nigromaculatus, the spine of the dorsal fin is straight and long, about as long as the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both have long, slender branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. ocellifer, the spine of the dorsal fin is short, a little shorter than the head, smooth in the front and serrated on the back, and curved. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is longer than the inner pair, and is about twice as long as the inner pair of barbels. Both pairs have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. omias, the spine of the dorsal fin is long, about as long or slightly longer than the length of the head, slightly curved, and smooth in the front and serrated on the back.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is a little under twice the length of the inner pair, and both pairs have short branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. macrostigma, the spine of the dorsal fin is about as long as the head, slightly curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have short, stiff branches near the base. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. multimaculatus, the spine of the dorsal fin is slightly shorter than the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have long branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. frontosus, the spine of the dorsal fin is short, about the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

External granular papilla are not present. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. grandiops, the spine of the dorsal fin is long, about as long as the head, is almost completely straight, contains up to three small serrations on the front and many small serrations on the back, and ends with short, white filaments. The remaining portion of the dorsal fin is made up of seven branching rays.

External sort, flat papilla are present and give the skin a pebbled appearance. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. ilebrevis, the spine of the dorsal fin is short, about as long as the head, slightly curved, rough on the front and serrated on the back, and ends with short, dusky filament. The remaining portion of the dorsal fin is made up of seven branching rays.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

A sciaenid has a long dorsal fin reaching nearly to the tail, and a notch between the rays and spines of the dorsal, although the two parts are actually separate. Drums are somberly coloured, usually in shades of brown, with a lateral line on each side that extends to the tip of the caudal fin. The anal fin usually has two spines, while the dorsal fins are deeply notched or separate. Most species have a rounded or pointed caudal fin.

The adult queen angelfish overall body color can be described as blue to blue-green with yellow rims on its scales. Their pectoral and ventral fins are also yellow but their lips and the edges of their dorsal fins and anal fins are dark blue. Queen angelfish are also known to have blue markings around each gill cover. Juveniles have dark blue bodies with yellow lips, gills, and tail and vertical bars ranging in color from light blue to white.

Their silver and elongated bodies make them difficult for prey to detect, and even more difficult to be seen when viewing them head-on. Barracudas depend heavily on their eyesight when they are out hunting. When hunting, they tend to notice everything that has an unusual color, reflection, or movement. Once a barracuda targets an intended victim, its long tail and matching anal and dorsal fins enable it to move with swift bursts of speed to attack its prey before it can escape.

The species within the genus Gymnocephalus have a number of characters in common including that their dorsal fins are not completely separate, they have enlarged canals extending from the lateral line on their heads, the preorbital bone covers the maxillary bone, presence of setiform or bristle-like teeth, having very few or no vomerine and palatine teeth and the possession of three paired bones in the neck, known as extrascapulars, in their lateral line system, of which, two are simple tubes.

The Gulf torpedo has a rounded pectoral fin disc, 84% as wide as long. The tail is short and stocky, bearing two small, subtriangular dorsal fins placed very close together, with the second three-quarters the size of the first. The pelvic fins are fleshy and partly fused to the disc, while the caudal fin is small and broadly rounded. The eyes are small; the spiracles are larger than the eyes in adults and bear 9-10 papillae on the rim.

External thin papilla are present but do not extend onto the fins. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. polli, the spine of the dorsal fin is short, about as long as the head, is slightly curved, is smooth on the front and finely serrated on the back, and ends with short, dark filament. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have slender, simple branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. victoriae, the spine of the dorsal fin is slightly shorter than the head, straight, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of six to seven branching rays.

Some remoras, such as this Echeneis naucrates, may attach themselves to scuba divers. Remoras are a family (Echeneidae) of ray-finned fish. They grow to long, and their distinctive first dorsal fins take the form of a modified oval, sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals. By sliding backward, the remora can increase the suction, or it can release itself by swimming forward.

The remoras , sometimes called suckerfish, are a family (Echeneidae) of ray- finned fish in the order Carangiformes. Depending on species, they grow to long. Their distinctive first dorsal fins take the form of a modified oval, sucker-like organ with slat-like structures that open and close to create suction and take a firm hold against the skin of larger marine animals. The disk is made up of stout, flexible membranes that can be raised and lowered to generate suction.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The outer pair of mandibular barbels is about twice as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. serratus, the spine is as long or a little shorter than the head, curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have long, slender branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. zambezensis, the spine of the dorsal fin is slightly curved, short, about as long as the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about or 2 times as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. sorex, the spine is slightly shorter to slightly longer as the head, straight or curved, serrated in the front and back. The remaining portion of the dorsal fin is made up of seven branching rays.

The adipose fin is large and the tail, or caudal fin, is forked. The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines. These spines can be raised into position at right angles to the body and locked into position for defensive purposes. The ability to lock the spines into place comes from several small bones attached to the spine, and once raised, the spines cannot be folded down by exerting pressure on the tip.

The large pectoral fins measure around one-fifth as long as the body, and have a falcate (sickle-like) shape tapering to a point. The first dorsal fin is of moderate size and somewhat falcate, with a pointed apex and a strongly concave rear margin; its origin lies over the pectoral fin free rear tips. The second dorsal fin is much smaller and is positioned about opposite the anal fin. A low dorsal ridge is present between the dorsal fins.

The gopher rockfish (Sebastes carnatus), also known as the gopher sea perch, is a rockfish of the Pacific coast, primarily off California. Gopher rockfish have a generally mottled appearance, with dark areas generally olive to reddish brown, and the lighter areas being white or sometimes pinkish. The upper part of the back almost always has three light patches extending into the dorsal fins, and the lighter areas become more extensive ventrally. They range in size up to about 40 cm.

In the course of its evolution, the caudal fin (tail) of the sunfish disappeared, to be replaced by a lumpy pseudotail, the clavus. This structure is formed by the convergence of the dorsal and anal fins, and is used by the fish as a rudder. The smooth-denticled clavus retains 12 fin rays, and terminates in a number of rounded ossicles. Ocean sunfish often swim near the surface, and their protruding dorsal fins are sometimes mistaken for those of sharks.

Restoration of H. fraasi Hybodus hauffianus Hybodus species grew to about in length, and are believed to have been opportunist predators. It was not very big, but had the classic streamlined shark shape, complete with two dorsal fins that would have helped it steer with precision. The mouth was not large, and rather than ruthlessly hunt large prey, Hybodus, was capable of eating a wide range of foods. They had several distinct features that made them stand apart from other primitive sharks.

It has no anal fin, but two dorsal fins approximately equal in size. The first dorsal fin originates about halfway from the tip of the snout to the tip of the caudal fin, the origin of the second dorsal fin is posterior to the tips of the pelvic fins. It has large pectoral fins, that's inner margins curve inward toward the base of the fins. There are dermal denticles on the dorsal surface of the body with very little overlapping.

Coelotilapia joka can reach up to about in total length. It originates from West Africa; found near the banks of clear rivers and tributaries of the lower parts of the Moa and Moro Rivers, southern Sierra Leone and northern Liberia and lives from the middle to the bottom of the river. Males have an elongated anal and dorsal fins and, with age, have white tips on their fins. In the wild, its diet is mainly herbivorous with some live foods taken.

There are two small dorsal fins, both with rounded to angular apices; the first is slightly smaller than the second, and its position varies from over to behind the pelvic fins. The caudal fin is triangular with rounded corners, and is roughly symmetrical above and below. The skin is soft and entirely devoid of dermal denticles. The dorsal coloration of the ocellated electric ray is extremely variable, with the only constant being the large ocellus ("eyespot") in the middle of the back.

The first dorsal fin is long-based and triangular, with the apex almost forming a right angle; the second dorsal fin is some two-thirds as high as the first. The origin of the first dorsal fin lies over the pectoral fin insertions, while that of second dorsal fin lies over the pelvic fin rear tips. No ridge exists between the dorsal fins. The anal fin is smaller than the second dorsal fin and has a strong notch in the rear margin.

The brown meagre is between 30 and 40 cm in length but can grow to 60 cm. It has a flat belly and its strongly arched back which give it an easily recognisable shape, the body is laterally compressed and the large, horizontal mouth reaches the level of the eye and contains villiform teeth. The anal and pelvic fins are black with an anterior white border. Both dorsal fins and the truncate caudal fin, are yellow with a black border.

In 1870 he reported seeing a new species of whale (unofficially called Giglioli's Whale) off the coast of Chile long with two dorsal fins observed by Giglioli from Magenta, a warship of the Italian Royal Navy.Matthew A. Bille, Rumors of Existence: Newly Discovered, Supposedly Extinct, and Unconfirmed Inhabitants of the Animal Kingdom, Hancock House, 1995, p. 158. The Rorqual is the only similarly configured whale in the fossil record. A similar whale was seen a year later off the coast of Scotland.

The Pacific cod is an important commercial food species. It has three separate dorsal fins, and the catfish-like whiskers on its lower jaw. In appearance, it is similar to the Atlantic Cod. A bottom dweller, it is found mainly along the continental shelf and upper slopes with a range around the rim of the North Pacific Ocean, from the Yellow Sea to the Bering Strait, along the Aleutian Islands, and south to about Los Angeles, down to the depths of .

The snout is short and blunt, with several enlarged thornlets at the tip. Its underside is smooth and its dorsal surface is densely covered with prickles. Two or three pairs of distinctive scapular thorns are on each shoulder, usually arranged in a triangle, and a row of 24-29 median thorns along the back, flanked by a row of smaller lateral thornlets on the tail. The tail is relatively short and tapering, with two similar-sized dorsal fins and no interdorsal thorn.

The Halloween darter can be distinguished from other members of its genus by possessing all the following traits: the branchiostegal membranes (membranes that connect the branchiostegal rays, which support the gill membranes) are slightly connected; the edge of the preopercle (bone between cheek and gill membrane) is not serrated; it usually has seven saddle-shaped color bands on its back; and males and females in breeding coloration have yellowish-orange or orange bands near the edge of their first dorsal fins.

The spines in the dorsal fins of female are alternately dark and uncolored whereas all the spines in the males dorsal fin are colorless, the membrane in the dorsal fin being clear in females and spotted in males. The cheek, gill cover and breast are scaleless while the belly and nape are scaled. When spawning the males darken, to almost black, on the head and the fins become more intensely colored. The maximum published total length is , although around is more common.

Molids mostly swim by using their anal and dorsal fins; the pectoral fins are probably just stabilizers. To steer, they squirt a strong jet of water out of their mouths or gills. They can also make minor adjustments in the orientation of the anal fin or the dorsal fin so as to control the amount of force it produces and the angle at which the force is produced. In this respect, they use their fins much like a bird uses its wings.

Sphyraena chrysotaenia has a very elongated, torpedo-shaped body, typical of the barracudas, with two well- separated dorsal fins, the first dorsal fin has with five spiny rays, with the first ray being the longest, the rays then progressively decrease in size posteriorly. The second dorsal fin has its origin in front of the origin of the anal fin. The tail is markedly forked. The pectoral fin sits directly below the origin of the first dorsal fin with the pelvic fin below it.

The caudal fin is rounded or concave. The overall colour of the body is tan with many black, brown and orange spots which meld together to create dark, vertical bars along the posterior of the ventral surface. There is a dark line that runs from the eye to the operculum and there are 6 or 7 in dark lines on the flanks. The anal, caudal, and the soft part of the dorsal fins are covered in a dense pattern of spots.

Due to the similarities between the common smooth-hound and other sharks, misidentification occurred for a long time. The common smooth-hound has two dorsal fins, an anal fin, a pair of pectoral fins, a pair of pelvic fins and a heterocercal tail. All of these fins help stabilise the shark but in males, the pelvic fins are modified to form claspers. Like other smooth hounds, the common smooth hound will aggregate in large numbers, like a pack of dogs.

The two dorsal fins are placed far back on the body, with the first originating about over the middle of the pelvic fin bases and the second originating over the anal fin. The second dorsal fin is much smaller than the first, and also smaller than the anal fin. Males have short and thick claspers. The caudal fin is short and broad, with a barely developed lower lobe and a strong ventral notch near the tip of the upper lobe.

The lesser African threadfin has a rather compress, moderately elongated body with has a depth which is around one thirds of the standard length. The mouth has an inferior position and is overhung by the blunt snout. The jaws extend past the eye. It has two dorsal fins which are widely separated, the first gorsal fin has 8 weak spines and the second has a single spine and 13 or 14 soft rays while the anal fin has 3 spines and 11 or 12 soft rays.

"What is a Lionchu?" by Peter Ponzio, an article from the Goldfish Pages Website (Goldfish Society of America), date retrieved: 26 May 2007 Furthermore, lionheads have short but deep bodies, and relatively straight or evenly arched backs without dorsal fins. The finnage, in general, is short. Breeding standards require that the lionhead’s anal fins are paired, the double tail fin should not droop, and its upper edges should be held away from the body."An Interpet Guide to Fancy Goldfish" by Dr. Chris Andrews, Interpet Publishing, 2002.

Originating below the fourth pair of gill slits, the pectoral fins are short, broad, and falcate (sickle-shaped) with pointed tips. The first dorsal fin is tall and falcate with a distinctively long free rear tip, and is positioned just behind the pectoral fin bases. The second dorsal fin is large and tall without a notably elongated free rear tip, and is positioned over or slightly behind the anal fin. Usually there is no midline ridge between the dorsal fins, and when present the ridge is slight.

The whitetail dogfish (Scymnodalatias albicauda) is a very rare sleeper shark of the family Somniosidae, found from the eastern Indian Ocean round southern Australia to New Zealand, at depths of between 150 and 500 m. Its length is up to 1.1 m. The whitetail dogfish is a rare species known only from a few specimens taken by tuna longliners and trawlers. The dorsal fins are small, the pectoral fins are angular, and there is an asymmetric caudal fin with a dark-tipped upper lobe.

Creek chubs can be effectively caught in minnow traps with dry dog food. More information is needed about effective daytime angling hours. Creek chubs are a hardy minnow that can easily be caught in small creeks, stored in aquariums, and used as bait to catch larger fish such as bass and catfish. Since creek chubs do not have sharp spines that make up their dorsal fins, like a bluegill or largemouth bass does, they may be a preferred food source for fish that prey on smaller fish.

Both of the jaws contain anteriorly widening bands of small villiform teeth, with larger individuals also having a number of conical outer teeth. There are two separate dorsal fins, the first consisting of 8 spines and the second of 1 spine and 18 to 20 soft rays. The anal fin comprises two detached anterior spines, followed by 1 spine and 14 to 17 soft rays. The lobes of both the soft anal and dorsal fin are falcate, with juveniles having the anteriormost rays extended into filaments.

There are two dorsal fins; the first is long and spiny, and is followed immediately by the second, which contains 1 tiny spine and 11–14 soft rays. The anal fin originates opposite the second dorsal fin and consists of 2 free spines followed by 1 spine and 10–12 rays. The dorsal and anal fins are followed by 6–7 finlets. There are two lateral lines, with the upper running to the rear of the first dorsal fin and the lower running to the caudal peduncle.

These spines protrude from nearly everywhere across the fish's body, including ones protruding from around the eyes, along a fleshy membrane surrounding the head, and between the scales of the back, concentrated mostly in a stripe on each side running laterally to the spine. The dorsal fins are broad and fan-like, with deep notches in the membrane between each spine.Jordan, David Starr, and Barton Warren Evermann. “Bulletin of the United States Fish Commission.” V.22 (1902) - Bulletin of the United States Fish Commission.

The longsnout dogfish (Deania quadrispinosa) is a little-known deepwater dogfish, found in the Atlantic and Indian Oceans from Namibia to Mozambique and in the South Pacific off southern Australia and New Zealand. The longsnout dogfish has an extremely long, angular snout, no anal fin, dorsal fins of similar size with the first placed high on the back and the second having a longer rear free tip, and pitchfork-shaped dermal denticles. It is dark brown and grows to about 114 cm. Reproduction is ovoviviparous.

They were probably relatively good swimmers, possessing dorsal fins, paired pectoral fins, and a strong tail. The shield of bone covering the head formed a single piece, and so presumably did not grow during adult life. However, the way in which the bone was laid down makes it possible to examine the imprints of nerves and other soft tissues. This reveals the presence of complex sensory organs and the sides and upper surface of the head, which may have been used to sense vibrations.

Males are territorial and court females by flashing their colourful dorsal fins; the fins are also used to brace receptive females during the vibratory release of milt and roe. The fish are nonguarders: the eggs are left to mix with the substrate. Although the Arctic grayling does not excavate a nest, the highly energetic courtship and mating tends to kick up fine material which covers the zygotes. The zygote is small (approximately in diameter) and the embryo will hatch after two to three weeks.

The cookiecutter shark (Isistius brasiliensis), also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been recorded as deep as . It migrates vertically up to every day, approaching the surface at dusk and descending with the dawn. Reaching only in length, the cookiecutter shark has a long, cylindrical body with a short, blunt snout, large eyes, two tiny spineless dorsal fins, and a large caudal fin.

There are 18-25 and 14-24 tooth rows on either side of the upper and lower jaws, respectively. The teeth have a slender central cusp flanked by a pair of small cusplets; those of adult males are slightly thicker than those of females. The body is fairly compressed from side to side and tapers towards the tail. The two dorsal fins are placed far back: the first originates over the rear of the pelvic fins while the second originates over the midpoint of the anal fin.

Andinoacara stalsbergi is a species of South American freshwater fish in the family Cichlidae. It was previously included in A. rivulatus, but was described as a separate species in 2009. The specific name honours the Norwegian aquarist Alf Stalsberg who collected the type of this species and who has had a “longstanding commitment to increase the knowledge about cichlid fishes”. A. stalsbergi has scales on the body with light centres and dark edges, and narrow clearly defined white edging to the tail and dorsal fins.

Roughly around the lateral line is a display of burnt orange- coloured spots interspersed with paler spots, with a single darker spot on the caudal peduncle. Males develop spectacular spawning colours in summer, namely a more brilliant display of orange spots along the side and to the tail. The anal and spiny and soft dorsal fins are edged with a tiny, iridescent, blue- white stripe. These stripes are somewhat subtle on most of the fins, but are prominent and eye-catching on the spiny dorsal fin.

The entire chest from underneath the pectoral fins to the base of the pelvic fins is scaleless. There are two separate dorsal fins, the first with eight spines and the second with a single spine followed by 19 to 22 soft rays. The anal fin has two detached spines before the major part of the anal fin, which consists of one spine and 17 or 18 soft rays. The pectoral and pelvic fins are both quite long, with the latter extending almost to the anal fin origin.

The cleftbelly trevally is a bluish green on the upper body which fades to silver on the underside of the fish. The membranes of the large pelvic fin are a distinctive black, while the remaining fins are a pale white colour. Juveniles have indistinct dark bands across their bodies, with a black spot becoming more prominent in adults. The species show sexual dimorphism in their dorsal fins, with mature males having between 6 and 12 elongated soft rays, strung out into filaments of varying lengths.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. nannoculus can be distinguished from other members of the genus Microsynodontis by examining the size of the eye. The diameter of the eye is only about 10% to 12% of the standard length of the fish, whereas the diameter of the eye of all other species in the genus ranges from about 13% to 26%.

Although the species is widely regarded as sexually monomorphic, males have been suggested to grow more quickly, and in some naturally occurring strains, males are noted to possess dark blotches on the base of their dorsal fins. The species reaches sexual maturity around one year of age, and continues to reproduce for 9–10 years. Frequency and timing of spawning may be related to the occurrence of rain. A. ocellatus fish are biparental substrate spawners, though detailed information regarding their reproduction in the wild is scarce.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have moderately long, simple branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. obesus, the spine of the dorsal fin is about times to as long as the head, slightly curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have short, simple branches, with secondary branches on the inner pair. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. nebulosus, the spine of the dorsal fin is slightly shorter than the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The anterior end of the organ has three long median projections, with the central extension the longest. The colour of the fish is a greenish grey above with the dorsal region of the head darker and whitish on the underside of the fish. The anterior and posterior dorsal fins are hyaline, with the first few membranes of the spinous dorsal fin dusted in tiny brown spots. The anal, ventral and pectoral fins are also hyaline, with the pectoral having a greenish upper margin and base.

As with other ptyctodonts, the armor of Ctenurella was reduced to a few thin plates on the head and shoulder region. It was also relatively small for a placoderm, at just in length. It had two dorsal fins, with that at the rear of the body being relatively long and low, and large pectoral and pelvic fins. Most ptyctodonts are presumed to have fed on the ocean floor, but the well- developed fins of this genus indicate that it probably also swam in open waters.

Adult freshwater eels are elongated with tubelike, snake-shaped bodies. They have large, pointed heads and their dorsal fins are usually continuous with their caudal and anal fins, to form a fringe lining the posterior end of their bodies. They have relatively well developed eyes and pectoral fins compared to saltwater eels that they use to navigate and maneuver through river bottoms and shallow water. Unlike most eels, freshwater eels have not lost their scales, and instead have soft, thin, scales that are embedded in the epidermis.

The upper teeth are exposed when the mouth is closed. The fourth and fifth pairs of gill slits lie over the pectoral fin bases and are shorter than the first three. The pectoral fins are rather small and angular, with nearly straight trailing margins. The two dorsal fins have rounded apices; the first is much larger and taller than the second, originating over the back half of the pelvic fin bases, while the second is positioned opposite the similarly-shaped but slightly larger anal fin.

The black goby is deeper-bodied than the common goby, sand goby and two-spotted goby with a more rounded snout and generally a larger size. It has two dorsal fins that are almost continuous, the anterior one having six spines, which may project from the fin membrane, and the posterior and shorter one having soft rays. The posterior dorsal fin terminates close to the caudal peduncle in contrast to the common and sand gobies where there is a long gap. The pelvic fins are fused.

There are 66–74 scales in the lateral line. The background colour of the head, body, and fins is brown, the body, caudal fin and dorsal fins are densely marked with irregular, small, dark brown spots. There are 2 dark brown stripes one of which runs from the eye across the gill cover while the other runs from the from maxillary groove to the lower margin of the preopercle. The juveniles are marked with horizontal dark stripes which dissolve into spots as they approach the caudal peduncle.

The Santa Ana sucker is closely related to the mountain sucker, and quite similar in appearance. Color is dark grey above and silvery-white below; the sides have a faint pattern of darker blotches and stripes. There are distinct notches where the upper and lower lips meet, and the lower lip is narrower in the middle, with only 3 or 4 rows of papillae at that point. The dorsal fins have 9 to 11 rays, while the pelvic fins have 8 to 10 rays.

External granular papilla are present and extend onto all of the fins. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. granulosus, the spine of the dorsal fin is long, about as long as the head, is almost completely straight, is smooth on the front and serrated on the back, and ends with short, black filament. The remaining portion of the dorsal fin is made up of seven to eight branching rays.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have short, simple branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. nigrita, the spine of the dorsal fin is straight or slightly curved, to 1 times the length of the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

A small black blotch id found on the bony flap covering the gills. The fish have two dorsal fins, two small detached spines in front of the rear fin and a deeply forked tail fin. At between two and four years of age the Silver trevally become sexually mature and is able to reproduce. Spawning happens in estuaries and in deeper waters between spring to autumn over an extended period, the females can produce between 50,000 and 200.000 eggs over the course of a season.

Thin papilla are present all over the head and body, but do not extend onto the fins. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. melanostictus, the spine of the dorsal fin is long, about as long as the head, slightly curved, smooth on the front and serrated on the back, and ends with short, black filament. The remaining portion of the dorsal fin is made up of seven branching rays.

Almost no sexual dimorphism occurs in this species, although males have more curved dorsal fins with broader bases and greater surface areas. The back of the dolphin is dark grey or black, and the dorsal fin is distinctively two-toned; the leading edge matches the back in colour, but the trailing edge is a much lighter greyish white. The dusky dolphin has a long, light-grey patch on its fore side leading to a short, dark-grey beak. The throat and belly are white,Webber, M.C. 1987.

The Melanotaeniidae is characterised by having their distal premaxillary teeth enlarged. They have a compressed body with the two dorsal fins being separated but with only a small gap between them. There are 3-7 spines in the first dorsal fin while the second has 6-22 rays, with the first ray being a stout spine in some species, the anal fin has 10-30 rays and, again, the first may be a stout spine in some species. The lateral line is either weakly developed or absent.

Of the two type specimens, the holotype had a total length (TL) of and a body length (BDL) of , while the paratype was slightly smaller, with a TL of and BDL of . The species has smooth skin and lacks scales. It has two dorsal fins, the first of which is upright and triangular and the second of which is longer and lower. The end of its tail fin has a "whip-like" fiber at the end of it and it lacks an anal fin.

The fins are yellowish except for the dark dorsal fins. The yellowfin croaker differs from other California croakers in having a single fleshy projection, a barbel, on the lower jaw and two heavy spines at the front of the anal fin. The diet of the yellowfin croaker consists mainly of small fishes and fish fry; however, invertebrates such as small crustaceans, worms and mollusks are also eaten in large numbers. Spawning takes place during the summer months when this species is most common along the sandy beaches.

Thomas, Pete, "SeaWorld killer whale's severe injury: accident or battle wound? ", GrindTV, October 1, 2012 Nakai is one of the only captive males over the age of 10 to not have a collapsed dorsal fin, other males such as Ikaika and Trua are younger, have shorter fins, and have fully collapsed dorsal fins. Nakai's dorsal fin is nearly tall and is slightly leaning to the left. The right side of his tail fluke is curved under but the left side has yet to curve.

Black dots of a few millimetres in diameter may also be found scattered all over the body, although the coverage of these dots varies between widespread to none at all. All the fins are generally light grey to black, although fish taken from turbid waters often have yellowish fins, with the anal fin being the brightest. The leading edges and tips of the anal and dorsal fins are generally lighter in colour than the main part of the fins. There is no black spot on the operculum.

Catsharks may be distinguished by their elongated, cat-like eyes and two small dorsal fins set far back. Most species are fairly small, growing no longer than 80 cm (31 in); a few, such as the nursehound (Scyliorhinus stellaris) can reach 1.6 m (5.2 ft) in length. Most of the species have a patterned appearance, ranging from stripes to patches to spots. Characteristics of genus Apristurus are mostly dark bodies, having a long anal fin that ends in front of where the lower caudal fin begins.

The yellowtail scad is a bright olive green above, transitioning to a more golden green ventrally, before becoming silvery white on the underside of the fish. Nine to 16 faint grey bars run vertically on the sides of the fish, as well as a black spot slightly smaller than the eye on the upper margin of operculum and adjacent shoulder region. The caudal and dorsal fins are a characteristic greenish yellow colour, the pelvic fins are white, while the rest of the fins are hyaline.

The inner pair of mandibular barbels is about to as long as the outer pair, have long, slender branches with secondary branches, and a membrane in the outer half. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. membranaceus, the spine is to as long as the head, straight or curved, smooth on the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

Mordacia mordax, known as the short-headed lamprey, Australian lamprey or Murray lamprey, is a species of Mordacia that lives in south-eastern Australia and Tasmania. Mordaciidae is made up of three species: M. praedox, M. mordax, and M. lapicida. M. mordax is a relatively rare, parasitic vertebrate and, along with the hagfishes, is part of the only surviving group of jawless organisms throughout vertebrate evolution. It has a thin eel-like body up to long, with two low dorsal fins on the back half.

When M. mordax is fully developed those anterior and posterior dorsal fins are well separated, which distinguishes them from northern hemisphere lampreys. Lampreys have been established as worthy models in understanding the development of higher vertebrate anatomy and physiology, with one such experiment determining that major classes of lipoproteins are similar in Mordacia to those found in humans. M. mordax and the lamprey group have also been shown to be the lowest vertebrate to have clear roles for neurohormones in the hypothalamic-pituitary-gonadal axis.

Of the two widely separated dorsal fins, the anterior fin is small and has four to five weak spines, while the posterior fin is larger, with one spine and eight or nine rays. The lengthy anal fin is somewhat sickle-shaped, has one spine and 16 to 18 rays. As befits the name, they are silvery on the sides; the back is somewhat yellowish, and the underside is a translucent greenish. These are small fish, with 15 cm recorded, but most adults 10 cm or less.

This species is a fairly large, deep-bodied fish with dark background coloration mixed with bright red spots scattered alongside the body. Nuptial males of this species also have deep green fins with orange margins on the spinous dorsal and caudal fins, with the soft dorsal fins having a dark coloration moving marginally to yellow-orangish center with black margins. This species can reach a length of TL though most only reach about . In 2011, the status of this fish was upgraded to State Endangered for Kentucky.

Snubnose darters reach sexual maturity at one year of age and only survive for one breeding season, which occurs in April to early May. The darter breeds in bedrock pools and crevices with low siltation. The testes of breeding males gradually begin to increase in size in January and reach their peak in April. Males also begin to develop bright breeding colors in January, and by April, all males are deep green to blue-green with red dorsal fins and red spots along their bodies.

The paradise threadfin is a medium-sized species of threadfin which attains a maximum length of , although the type of measurement used was not given, a more normal length is a total length of . It has a pointed snout and the head's dorsal profile is almost horizontal. There are two separate dorsal fins, the first dorsal fin has 8 spines with each one having a base of a similar size to the others. The second dorsal fin contains a single spine and 14 or 15 soft rays.

Since barnacles require that water flow independently over them to filter food, colonies may follow the direction of water currents produced by the animal in areas with moderate flow. However, Xenobalanus exclusively inhabits the most turbulent environments for barnacles on flippers, flukes, and dorsal fins. Barnacle larvae may reach these sites passively, being deposited naturally by vortexes created by the animal, or may crawl to more suitable locations. Xenobalanus stimulates the growth of calcified skin around itself which prevents the skin from shedding and dislodging the barnacle.

Polydactylus sexfilis is a medium-sized species, which attains a maximum total length of and a weight of . It has a ponted snout and the head has an almost horizontal profile. There are two separated dorsal fins, the first dorsal fin has 8 spinesand the second dorsal fin contains a single spine and 12 or 13 soft rays. The anal fin has 3 spines and 11 or 12 soft rays, the base of the anal fin is roughly equal in length to the second dorsal-fin base.

The mouth is large and arched, with short but prominent furrows around each corner. There are around 65 upper and 61–65 lower tooth rows; each tooth has a narrow central cusp flanked by 3–5 smaller cusplets. There are five pairs of gill slits; the fourth and fifth are located over the pectoral fin bases and closer together than the others. The small dorsal fins have blunt apexes and straight to gently convex trailing margins; the first is slightly taller but shorter- based than the second.

They are frequently seen basking in the sun near the surface and are often mistaken for sharks when their huge dorsal fins emerge above the water. Their teeth are fused into a beak-like structure, and they are unable to fully close their relatively small mouths. Ocean sunfish can become so infested with skin parasites, they will often invite small fish or even birds to feast on them. Sunfish will even breach the surface up to in the air, in an attempt to shake the parasites.

The first dorsal fin is triangular with a rounded apex, originating in front of the pelvic fin insertions. The second dorsal fin is only one-half to two- thirds as large as the first; the distance between the dorsal fins is less than the length of the first dorsal fin base. The stout tail comprises about one-third of the total length, terminating in a caudal fin shaped like an equilateral triangle with slightly convex margins. The skin is soft and completely devoid of dermal denticles (scales).

There are 32-34 upper tooth rows and 21-29 lower tooth rows; each tooth has an upright, awl-shaped central cusp and a pair of lateral cusplets. The five pairs of gill slits are small, with the fifth pair close to the fourth. The pectoral fins are large and broad, with rounded margins. The two dorsal fins are roughly equal in size and have rounded apices and angular free rear tips; the first dorsal fin originates over the bases of the pelvic fins.

The king threadfin is a large threadfin which can attain a maximum total length of and a maximum published weight of , although the more common total length is . It has a pointed snout and the dorsal profile of the head is almost flat in young fish and concave in adults. There are two separate dorsal fins, the first dorsal fin has 8 spines and the second spine is thicker than others. The second dorsal fin has a single spine and 11 to 13 soft rays.

Pseudogobiopsis oligactis is a species which has a relatively slender, cylindrical body with two dorsal fins, a rounded tail and which has the pelvic fins fused into a disc. There is a count of 22–25 scales in the lateral line. The scales on the upper part of body have narrow blackish margins and the flanks are marked with five elongated dark brown blotches along their middle with five black spots underneath them. There are three blackish streaks on the sides of the face.

Least puffers are tetraodontids, meaning their teeth have fused into beaks with a median division that produces two plates in the upper and lower jaw.Walls, J.G. (1975) Fishes of the Northern Gulf of Mexico. Neptune City: T.F.H. Publications Inc. pp. 408,411 Tetraodontids can also be characterized by their lack of fin spines or ribs, and a tough skin that is often covered with small spinulous scales. They typically have dorsal fins containing 8-9 rays and their pectoral rays are usually within the number range of 13-16.

Electrolux addisoni is easily distinguished from other narkids by its striking colour pattern consisting of a dark brown dorsal surface of the disc with numerous small pale yellow spots and a series of concentric stripes. It can also be distinguished by its large spiracular papillae. It and Heteronarce are the only genera in the family Narkidae that have two dorsal fins. The conspicuous colour pattern of the species may act as a warning signal to other animals, when closely approached the ray has been seen to make a possible threat display.

The head of the Chinese sleeper The invasive Chinese sleeper from the region of Vinnytsia, Ukraine The Chinese sleeper, known as rotan in Russia, resembles a perch, ruffe or sculpin. The eyes are placed high on the head which has a rounded snout and projecting lower jaw. There is little or no gap between the two dorsal fins, the front one of which has six to eight spines and the back one nine to eleven soft rays. The anal fin has one to three spines and seven to ten soft rays.

Reaching a maximum known length of , the mottled skate has a diamond-shaped pectoral fin disc with a broad, elongated snout that tapers to a point. The length of the head from above is less than four times the distance between the eyes. A notch is in the posterior margin of each pelvic fin. The tail bears a fold running along each side and two small dorsal fins positioned near the tip; the caudal fin is reduced to a low fold no deeper than the lateral tail folds.

The Latidae, known as the lates perches, are a family of perch-like fishes found in Africa, Asia, and the Indian and western Pacific Oceans. Including about 13 species, the family, previously classified subfamily Latinae in family Centropomidae, was raised to family status in 2004 after a cladistic analysis showed the original Centropomidae were paraphyletic. The Latidae are characterised by having dorsal fins that are incompletely separated, or if they are separated, a few isolated spines will be found between the anterior and posterior parts of the fin. Their caudal fin is normally rounded.

Polydactylus sextarius is a small- to medium-sized threadfin which attains a maximum total length of but is more common. It has a pointed snout with the dorsal profile of the head being almost straight. There are two separate dorsal fins, the first with 8 similar spines and the second dorsal fin has a single spine and 12 or 13 soft rays. The anal fin has 3 spines and 11 to 13 soft rays, with the anal fin base being roughly the same length as the base of the second dorsal fin.

Most have two dorsal fins, the first made up from spiny fin rays, while the other has some spines in the front followed by numerous soft rays. They are most plentiful in the tropical and subtropical regions, but as a group are almost cosmopolitan in marine ecosystems. A few species tolerate brackish water, and some – Padogobius and Pomatoschistus species – even inhabit fresh water. They are generally benthic as adults (the spawn can distribute widely by ocean currents), only Sufflogobius bibarbatus is noted to be quite pelagic throughout its life.

The fish has a long and slender body. It also has eight dorsal fin-rays, anywhere from nine to eleven anal fin-rays, thirteen to fourteen pectoral fin-rays and eight pelvic fin-rays. The fish has a dark spot of pigment at the base of its first few dorsal-fins, which distinguishes Lythrurus ardens from similar looking fish in its habitat. In addition, the fish has a stripe that fades as it approaches the dorsa fin and several bands of coloration across the back of the fish.

The finless sleeper ray was described as a new species and genus by English zoologist John Edward Gray in an 1831 issue of the scientific journal Zoological Miscellany. His account was based on two specimens collected from Penang in Malaysia by General Thomas Hardwicke and presented to the British Museum. Hence, Gray named the ray Temera hardwickii, or "Hardwicke's Temera". He noted that the new genus was most closely affiliated to the genus Narke, because it has no dorsal fins while Narke has only one and other electric rays have two.

The Arabian carpetshark (Chiloscyllium arabicum) is a species of carpet shark in the family Hemiscylliidae, inhabiting coral reefs and other shallow coastal habitats from the Persian Gulf to India. Reaching long, this shark is characterized by a slender, plain brown body, and by two dorsal fins with straight trailing margins and the second smaller but longer-based than the first. The Arabian carpetshark feeds on bony fishes and invertebrates. Reproduction is oviparous with an annual cycle; females deposit egg capsules four at a time and the young hatch after 70-80 days.

The asymmetrical caudal fin has a well-developed lower lobe and a longer, narrow upper lobe with a strong ventral notch near the tip. The dermal denticles are small and overlapping, each with three horizontal ridges leading to marginal teeth. This species is slate-gray above, darkening towards the tips of the dorsal fins and upper caudal fin lobe; some specimens have irregular rows of small, white blotches, which may be an artifact of handling. The underside is white, which extends onto the flanks as a vague pale band.

The yellow perch has an elongate, oval body with a relatively long but blunt snout which does not reach past the tip of the lower jaw. Like most perches it has two separate dorsal fins The anterior, or first, dorsal fin contains 12-14 spines while the second has 2-3 spines in its anterior followed by 12-13 soft rays. The anal fin has 2 spines and 7-8 soft rays. The upper part of the head and body varies in colour from bright green through to olive or golden brown.

Ultraman featured new monster suits, as well as recycled suits from Ultra Q. Two Godzilla suits were recycled from Toho for the monster Jiras, with the head of the Godzilla suit from Ebirah, Horror of the Deep placed upon the body of the Godzilla suit from Mothra vs. Godzilla. The dorsal fins and parts of the suit were sprayed yellow and a large yellow frill was added to disguise the connection of the head with the body. The show also marks the first appearance of Ultraman Zoffy in the finale Farewell, Ultraman.

The dorsal and ventral profiles of the fish are nearly evenly convex, with the two profiles intersecting at the pointed snout. There are two separate dorsal fins; the first consisting of 8 moderately high spines and the second of a single spine followed by 18 to 20 soft rays. The anal fin consists of two anteriorally detached spines followed by a single spine attached to 16 or 17 soft rays. In both the dorsal and anal fins, the posterior 7-10 rays are detached and form a series of diagnostic finlets.

The Seychelles gulper shark (Centrophorus seychellorum) is a species of fish in the family Centrophoridae found in Alphonse island in Seychelles. This species is distinguished by having large tip of snout to first dorsal distance of 34% TL; first dorsal fin high (7% TL); second dorsal fin base long (9.8% TL); long snout (12.2% TL); uniformly grey with tip and the trailing edge of dorsal fins blackish.Baranes, A. (2003): Sharks from the Amirantes Islands, Seychelles, with a description of two new species of squaloids from the deep sea. Israel Journal of Zoology, 49: 33-65.

Measuring between long, these rays have oval to diamond-shaped pectoral fin discs and relatively short tails that terminate in leaf-shaped caudal fins, and may also have small dorsal fins and lateral skin folds. Most are smooth-skinned, and some have ornate dorsal color patterns. Stingarees feed on or near the sea floor, consuming small invertebrates and occasionally bony fishes. They are aplacental viviparous, meaning their embryos emerge from eggs inside the uterus, and are sustained to term first by yolk and later by maternally produced histotroph ("uterine milk").

Radiation of elasmobranchs, based on Michael Benton, 2005. Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including the sharks (superorder Selachii) and the rays, skates, and sawfish (superorder Batoidea). Members of this subclass are characterised by having four (tawny nurse sharks have 4 pairs of gills) to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper.

Atlantic bonito belong to a group which have the dorsal fins very near, or separated by a narrow interspace. Its body is completely scaled, with those scales in the pectoral fin area and the lateral line usually larger in size. Bonitos (fishes in the genus Sarda) differ from tuna by their compressed bodies, their lack of teeth on the roof of the mouth, and certain differences in colouration. Atlantic bonito share Atlantic waters with the striped bonito, Sarda orientalis (the Atlantic population of which is sometimes considered a separate species, Sarda velox).

This is compensated by an enhanced sense of touch in the anterior rays of the dorsal fins, the lateral lines along the body. The anterior rays are used to sense prey buried under sediment, or in turbulent water, and the lateral lines detect waves of pressure and low-frequency sound in the water. This species also has fin rays modified with taste buds, and a tongue and more taste buds located on the blind side of the head. These help the flounder to distinguish prey from any unwanted matter as it eats.

DHC-1 Chipmunk Anti-spin leading edge strakes, or spin strakes, or antispin fillet Nasa TN D-6575, Summary of spin technology as related to the light general-aviation airplanes, fig. 10 may be placed at the tailplane roots of generally aerobatic aircraft, such as the de Havilland Tiger Moth (British version), Scottish Aviation Bulldog, and de Havilland Canada DHC-1 Chipmunk.Daroll Stinton, The design of the aeroplane, Lateral and directional stability and spinning, p.461. Ventral or dorsal fins increasing the directional stability are also used as anti-spin devices.

The arrow goby is a small, pale grey, translucent fish which grows to in length. It has two dorsal fins; the first is the shorter and has 4-5 spines while the dorsal fin has 15-17 soft fin rays. The anal fin is about equal in length to the second dorsal fin and has 14-17 fin rays. Like other gobies, the caudal fin is rounded and the pectoral fins form a cone which the goby uses to prop the anterior part of its body above the substrate.

The leopard catshark (Poroderma pantherinum) is a species of catshark, and part of the family Scyliorhinidae, endemic to the coastal waters of South Africa. Abundant in inshore waters under deep, this bottom-dweller favors rocky reefs, kelp beds, and sandy flats. Growing to a length of , the leopard catshark has a stout body with two dorsal fins placed well back, and a short head and tail. It is extremely variable in color and pattern, with individuals ranging from almost white to black and covered by diverse patterns of black spots, blotches, rosettes, and/or lines.

The body is rather laterally compressed and tapers towards the tail, with two dorsal fins set far back. The first dorsal fin originates over the rear of the pelvic fins and is much larger than the second, which originates over the midpoint of the anal fin base. The bases of the pectoral and pelvic fins are about equal; the pectoral fins are large and broad while the pelvic fins are much lower. Adult males have stubby claspers with the inner margins of the pelvic fins partially fused over them to form an "apron".

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. nasutus can be distinguished from other members of the genus Microsynodontis by examining the length of the snout. In M. nasutus, the snout is longer, with a length of about 50% to 53% of the standard length of the fish, whereas other species in the genus have shorter snouts, raning from about 36% to 50% of the standard length.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. vigilis can be distinguished from other members of the genus Microsynodontis by examining the length of the adipose fin, the size of the eye, the shape of the pectoral spine, and the shape of the caudal fin. The length of the adipose fin is shorter than most species, and has a larger eye than most species.

The outer pair of mandibular barbels is about as long as the inner pair, have long, slender branches with secondary branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. filamentosus, the spine is as long as the head, curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays, ending in a long elongated filament that is longer than the dorsal fin itself.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have long branches. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. caudovittatus, the spine of the dorsal fin is slightly curved, long, about as long or a little shorter than the head, smooth or finely serrated in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The body is slender and of moderate size, and is grey to greyish-brown in colour, with a paler underside. Of the two dorsal fins, the first is larger than the second, and each has a short spine, a white rear margin, and a dark blotch towards the front, which is more distinct in juveniles. The large caudal fin is asymmetrical, with a longer upper than lower lobe. The broad teeth of this species differ between the upper and lower jaws, with the lower teeth being much larger.

The outer pair of mandibular barbels is about twice the length of the inner pair, and both pairs have moderately long, simple branches, with secondary branches on the inner pair. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. melanopterus, the spine of the dorsal fin is as long as or slightly shorter than the head, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

There are two widely separate dorsal fins, the first is triangular with 8 spines and the second has one spine with 28-33 soft rays. The anal fin has 2 detached spines followed by a single spine and 25-29 soft rays; the terminal dorsal and anal soft rays consist of a widely detached finlet. The pectoral fin measures 76.5 to 97.0% of the head length. In life it is bluish- green above and silvery below with a small black blotch on the margin of operculum near its upper edge.

The scales on the head and front half of the body are large while those on the hind half are smaller and smooth. This fish is predominantly pale grey, greenish-grey or yellowish-brown. The body has three indistinct broad dark bars and there is a pale streak on the chin. The upper part of the orbit of the eye is blue and there are some small blue spots and lines on the dorsal fins and upper parts of the body, and sometimes white dots and irregular lines on the lower parts of the body.

The vundu is the largest true freshwater fish in southern Africa, reaching up to in length and in weight. (Bull sharks are also found in southern Africa and reach a larger size, but occur in both fresh and saltwater.) Few other catfish have such large second dorsal fins (adipose fins) or such long barbels as do the vundu. Its barbels nearly reach to the origin of the pelvic fin. The colour of Heterobranchus longifilis is light to dark olive brown on its dorsal surface, getting lighter over the mid-body to a light brown.

The Gadidae are a family of marine fish, included in the order Gadiformes, known as the cods, codfishes, or true cods. It contains several commercially important fishes, including the cod, haddock, whiting, and pollock. Most gadid species are found in temperate waters of the Northern Hemisphere, but several range into subtropical, subarctic, and Arctic oceans, and a single (southern blue whiting) is found in the Southern Hemisphere. They are generally medium- sized fish, and are distinguished by the presence of three dorsal fins on the back and two anal fins on the underside.

The orangebelly goby is short in length with an indented forehead, and as suggested by the name is primarily orange in colour. The dorsal fins are covered by yellow stripes, whilst the body ranging from the head to the base are covered in khaki stripes, some of which are comparatively longer in length. The species can be distinguished from close relatives by unbranched pelvic rays, the presence of elongated tips on four of the pelvic rays, a fifth vestigial pelvic ray, a bilobed tongue and scales beneath the leading dorsal fin.

Great barracuda hovering in the current at the Paradise Reef, alt=Photo of barracuda with coral swimming above coral Barracuda are snake-like in appearance, with prominent, sharp-edged, fang-like teeth, much like piranha, all of different sizes, set in sockets of their large jaws. They have large, pointed heads with an underbite in many species. Their gill covers have no spines and are covered with small scales. Their two dorsal fins are widely separated, with the anterior fin having five spines, and the posterior fin having one spine and 9 soft rays.

The marbled electric ray has a nearly circular pectoral fin disc and a muscular tail that bears two dorsal fins of nearly equal size and a large caudal fin. It can be identified by the long, finger-like projections on the rims of its spiracles, as well as by its dark brown mottled color pattern, though some individuals are plain-colored. Males and females typically reach and long respectively. Nocturnal and solitary, the marbled electric ray can often be found lying the sea floor buried except for its eyes and spiracles.

The western shovelnose stingaree (Trygonoptera mucosa) is a common species of stingray in the family Urolophidae, inhabiting shallow sandy flats and seagrass beds off southwestern Australia from Perth to Gulf St Vincent. Growing to long, this small ray has a rounded pectoral fin disc and a blunt, broadly triangular snout. Its nostrils have enlarged lobes along the outer rims and a skirt-shaped curtain of skin between them with a strongly fringed posterior margin. Its tail ends in a lance-like caudal fin and lacks dorsal fins and lateral skin folds.

The longnose pygmy shark (Heteroscymnoides marleyi) is a rare species of squaliform shark in the family Dalatiidae and the only member its genus. It is known only from a handful of specimens collected from the cold oceanic waters of the Southern Hemisphere, between the surface and a depth of . Reaching in length, this diminutive shark is characterized by a slender, dark brown body with a very long, bulbous snout. In addition, it has two spineless dorsal fins of nearly equal size, with the origin of the first lying over the pectoral fin bases.

The rest of the general body plan of the genus is similar to other carangids, with two separate, rather low dorsal fins; the first consisting of 8 spines and the second of 1 spine and 25 to 29 soft rays. The anal fin is also low, consisting of 2 detached spines anteriorly, followed by 1 spine and 25 to 29 soft rays. The lateral line is moderately curved anteriorly, with six to 14 weak scutes on the straight section. The chests are completely scaled, and the jaws contain bands of fine villiform teeth.

The exact purpose of the skin folds is not known, but is a characteristic of the species of Syndontis that are endemic to Lake Tanganyika. External granular papilla are present on the head, but not the body. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. petricola, the spine of the dorsal fin is long, about as long as the head, is slightly curved, is smooth on the front and with fine serrations the back, and ends with short, white filament.

The carpet sharks are a diverse group of sharks with differing sizes, appearances, diets, and habits. They first appeared in the fossil record in the Early Jurassic; the oldest known orectolobiform genera are Folipistrix (known from Toarcian to Aalenian of Belgium and Germany), Palaeobrachaelurus (Aalenian to Barremian) and Annea (Toarcian to Bajocian of Europe). All species have two dorsal fins and a relatively short, transverse mouth that does not extend behind the eyes. Besides the nostrils are barbels, tactile sensory organs, and grooves known as nasoral grooves connect the nostrils to the mouth.

Callionymus reticulatus, the reticulated dragonet, is a species of dragonet native to the northeastern Atlantic Ocean and the Mediterranean Sea where it is found at depths of from . This species grows to a length of TL. This species has a flattened head and body, the head has a triangular shape with the eyes placed on the top of the head. It has two dorsal fins with the first one being triangular in shape. It has blue spots along the flanks and four saddle-like markings on their backs which have sharply defined outlines.

The Gangetic whiting, Sillaginopsis panijus (also known as the flathead sillago), is a species of inshore marine and estuarine fish of the smelt- whiting family, Sillaginidae. It is the most distinctive Asian member of the family due to its flattened head and trailing dorsal fins. Although first described in 1822, it was not placed in its own genus until 1861 when Theodore Gill erected Sillaginopsis, a genus which is still monotypic. Gangetic whiting are of minor commercial importance along the Southeast coast of the Asian continent where it inhabits protected areas.

The Diassanga mullet has a rounded, rather robust body with a pointed head which is about a quarter of the length of the body. The eye is surrounded by a small rim of adipose tissue and its upper lip has a thickness equal to a third of the diameter of the eye while the lower lip is much thinner. It has a silvery blueish-grey back with paler flanks which are marked with seven longitudinal grey lines. The anal and dorsal fins are yellow, as is the caudal fin but this has a black margin.

Fish, as vertebrata, developed as sister of the tunicata. As the tetrapods emerged deep within the fishes group, as sister of the lungfish, characteristics of fish are typically shared by tetrapods, including having vertebrae and a cranium.alt=Drawing of animal with large mouth, long tail, very small dorsal fins, and pectoral fins that attach towards the bottom of the body, resembling lizard legs in scale and development. Lower jaw of the placoderm Eastmanosteus pustulosus, showing the shearing structures ("teeth") on its oral surface; from the Devonian of Wisconsin.

The outer pair of mandibular barbels is a little under twice the length of the inner pair; and the outer pair with moderately long branches and the inner pair with secondary branches present. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. robbianus, the spine of the dorsal fin is about to times the length of the head, slightly curved, smooth in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The tail is shorter than the disc, with two small, equally sized dorsal fins and a rudimentary caudal fin. The eyes and mouth are large; the teeth are pointed and number about 64 in the upper jaw and 56 in the lower. The upper surface is rough in texture, with patches of large spines on the snout, around the eyes, and on the shoulder. There are two rows of about 50 spines each running from the center of the back to the first dorsal fin, and no interdorsal spine.

Other internal parasites included the cestodes Diphyllobothrium macroovatum, Diplogonoporus balaenopterae, and Tetrabothius sp., which infected the small intestine and were found in 17 per cent of the sample (all three species combined). In the eastern North Pacific, forty-three of forty-four individually identified minke whales possessed what were believed to be scars from cookiecutter sharks, while three had individuals of the commensal barnacle Xenobalanus globicipitis attached to their dorsal fins. Both are primarily warm water species and may be evidence of migration for minke whales from British Columbia to tropical waters.

The bellowfishes or bellowsfishes are fishes in the genus Notopogon in the family Centriscidae. They are found in deeper parts of the temperate southern oceans, although the longspine bellowfish has been recorded as far north as New Caledonia and Madagascar. According to FishBase, they are part of the family Centriscidae, but some authorities split that family, in which case the genus Notopogon is in the family Macroramphosidae, which is followed here. They have long second spines on their dorsal fins and tiny mouths at the tip of their greatly elongated snouts.

The birdbeak dogfish (Deania calcea) is a dogfish shark of the family Centrophoridae found in the Pacific Ocean around Honshū, Japan, southern Australia, New Zealand, and Chile, and in the Atlantic Ocean from Iceland south to the Cape of Good Hope. The birdbeak dogfish has a very long, narrow snout, no anal fin, two long and low dorsal fins with grooved spines, small rectangular pectoral fins, and pitchfork-like denticles. It lives at depths between 73 and 1,450 m. It is ovoviviparous with up to 12 pups per litter.

The mosaic gulper shark (Centrophorus tessellatus) is a small rare deepwater dogfish, found in the Pacific Ocean around Honshū, Japan and the Hawaiian Islands at depths between 260 and 730 m. It is one of 13 described species in the genus Centrophorus. The mosaic gulper shark has no anal fin, two dorsal fins with large spines (the second dorsal is relatively high, almost as high as the first), large eyes, angular extended free tips on the pectoral fins, and a moderately notched caudal fin. It has a maximum length of 89 cm.

The caudal fin has a well-developed lower lobe and a notch near the tip of the upper lobe. The dermal denticles are oval with five horizontal ridges leading to marginal teeth. The most distinctive trait of this species is its coloration: the back and dorsal fins are gray to yellowish gray, and the cephalofoil margins, flanks, underside, pectoral fins, pelvic fins, and anal fin are bright yellow to orange with a metallic or iridescent sheen. Newborn sharks are gray above, darkening on the first dorsal fin and upper caudal fin lobe, and whitish below.

Māui dolphins are physically very similar to South Island Hector's dolphins. They are most easily differentiated from other New Zealand cetacean species by: their distinctive grey, white, and black markings; a short snout; unique, rounded dorsal fins; and small, but solidly-built bodies (Hector's dolphins are the smallest dolphin species globally). Female Māui dolphins grow to 1.7 m long and weigh up to 50 kg; males are slightly smaller and lighter. The life history of Māui dolphins is assumed to be very similar to that of South Island Hector's dolphins.

The first of the two dorsal fins is spinous, with 4-8 spines; in some species, this fin is completely overgrown with skin and therefore not visible. While the lateral line in lumpsuckers is otherwise reduced or absent, it is well developed in the head; some species even have tubular, whisker-like external projections of the opercular canal, which is a part of the cranial lateral line system. The relatively small mouths of lumpsuckers are lined with narrow rows of small conical teeth. The gas bladder is absent.

Lam I – VI. The tail is attached just behind the anus and is bent forward to pass near the mouth. The tail has ventral and dorsal fins running along its length. However, because it is twisted through a right angle, it appears to have fins on its left and right sides and it undulates up and down rather than from side to side. The exoskeleton of this class of tunicates consists of a mucus net which is known as a "house" and surrounds the animal's body like a bubble.

The eyes of Mordacia are dorsolaterally located, which is unlike the other known lamprey species, and they contain a photoreceptor that has both rod and cone characteristics. This photoreceptor is also unique to M. mordax and enhances vision in darkness by optimizing photon reception. It is not unlike deep sea fish eye anatomy, in that sense as M. mordax only comes out of the sediment of rivers at night to travel. The posterior and anterior dorsal fins of Mordacia are continuous to the caudal fin, unlike G. australis.

Two small dorsal fins are on the tail, the anal fin is absent, and the caudal fin is reduced to a simple fold. There is a weak notch in each pelvic fin. A juvenile has smooth skin, while an adult has small prickles on its dorsal surface and the underside of the snout, between the gill slits, and on the abdominal region. It has two or three thorns on the middle of the back, a row of 12-55 (usually 13-17) thorns along the midline of the tail, and an interdorsal thorn.

Reaching in length, the thornback guitarfish has a heart-shaped pectoral fin disc and a long, robust tail bearing two posteriorly positioned dorsal fins and a well- developed caudal fin. The most distinctive traits of this plain-colored ray are the three parallel rows of large, hooked thorns that start from the middle of the back and run onto the tail. Encountered singly or in groups, the thornback guitarfish feeds on small, benthic invertebrates and bony fishes. It is aplacental viviparous, with the developing young drawing sustenance from a yolk sac.

The whitefin trevally has a deep, almost rhomboid-shaped body The whitefin trevally is a relatively small fish, reaching a maximum known length of 37.5 cm. The species has a body shape similar to a number of other jacks, having a compressed, almost rhomboidal body, with the dorsal and ventral profiles approximately equally convex. The dorsal profiles of the snout and nape in the species are almost straight. Two separate dorsal fins are seen, with the first having seven spines, while the second consists of one spine and 23 to 25 soft rays.

The yellowfin whiting is a sandy brown to pale silvery grey colour, with a darker dorsal surface and paler underside. There is a narrow silver mid-lateral band with a brownish band above, although these bands may be pale or indistinct. The dorsal fins are both hyaline with rows of small brown spots and the anal fins are pale yellow with a cream margin. The ventral fins are also yellowish, and the pectoral fin is pale yellow to hyaline with a fine dusting and lacks a dark spot at the base.

The lateral-line is simple and runs from the upper end of the gill slit to the middle of the rear margin of the caudal fin, the lateral line contains 66-71 pored scales. The head and body are greyish-black above and yellow below, The front parts of both dorsal fins are greyish black with the rest of the fins being pale yellow. The pectoral and pelvic fins are completely a vivid yellow. The pectoral filaments are bright yellow at their base fading to whitish yellow at their tips.

The size of this species ranges from 600–2000 mm, displaying sexual dimorphism where the females are significantly larger than the males. The large pectoral wing like fins on the sides of its body project it through the water and allow for additional lift, whilst the long tapered tail adds to its agility in the water. Members of the family Chimaeridae carry a venomous dorsal fin spine as a defense mechanism to ward off predators. Whilst members of the family have two dorsal fins, it is only the primary one that contains venom.

Off northwestern Madagascar, six different cow-calf pairs were seen: one in August 2011, three in November 2013, and two in August 2015, suggesting a protracted calving season. The three calves observed in November had bent dorsal fins (indicating that they were fairly young) but did not have fetal folds, while one of the calves sighted in August had an erect dorsal fin, indicating that it was older but still probably born that year. These calves were estimated to range in length from 3 to 5 m (9.8 to 16.4 ft).

Humpback dolphins are members of the genus Sousa. These dolphins are characterized by the conspicuous humps and elongated dorsal fins found on the backs of adults of the species. They are found close to shore along the coast of West Africa (Atlantic species/variety) and right along the coast of the Indian Ocean from South Africa to Australia (Indo-Pacific species/varieties). Several institutions have made a proposal to divide the Indo-Pacific species into two distinct species: the Indo-Pacific humpback dolphin and the Australian humpback dolphin.

There is a dark brown stripe which runs from the maxillary streak to margin of the preopercle; the anal and dorsal fins are darker with white spots and streaks. The body is oblong and compressed with a depth of 2.7-3.2 times in standard length. It has a convex interorbital area; angular preopercle which has enlarged serrations at its angle which forms an indistinct lobe; the anterior and posterior nostrils are differing in size. It normally reaches around 4 kg in weight, although there are reports of specimens weighing up to 10 kg.

Pharyngolepis is an extinct genus of primitive jawless fish that lived in the Silurian period of what is now Norway. reconstruction Pharyngolepis had well- developed anal and caudal fins, but no paired or dorsal fins that would have helped stabilise it in the water, and so was probably a poor swimmer, remaining close to the sea bottom. The pectoral fins were instead replaced by bony spines, possibly for protection against predators, and there was a row of spines along the back. It probably scooped up food from the ocean floor.

The first dorsal fin is relatively small, measuring less than a tenth as high as the shark is long, and originates behind the free rear tips of the pectoral fins. It has a rounded apex, an "S"-shaped rear margin, and a free rear tip about half as long as the fin is tall. The second dorsal fin is tiny, smaller than the anal fin, with a drawn-out free rear tip up to three times as long as the fin is tall. A narrow dorsal ridge runs between the dorsal fins.

Like other members of its genus, it has an almost circular pectoral fin disk with a nearly straight leading margin, and a robust tail with a large triangular caudal fin. Distinctive characteristics include its uniform dark color, smooth-rimmed spiracles (paired respiratory openings behind the eyes), and two dorsal fins of unequal size. Solitary and nocturnal, the Atlantic torpedo is capable of generating up to 220 volts of electricity to subdue its prey or defend itself against predators. Its diet consists mainly of bony fishes, though it also feeds on small sharks and crustaceans.

The bluegrey carpetshark or Colclough's shark (Brachaelurus colcloughi) is an uncommon species of carpet shark endemic to shallow inshore waters off northeastern Australia. It is one of the two extant members of the family Brachaeluridae. The bluegrey carpetshark has a stocky body with a wide, slightly flattened head, dorsally placed eyes, and a pair of long barbels with posterior skin flaps. It has large pectoral fins, two dorsal fins of unequal size placed far back on the body, and a sizable space between the anal fin and the base of the caudal fin.

While the rest of their bodies is shaped similarly to other fish that inhabit the areas they frequent, their heads are triangle-shaped and dorsoventrally depressed, giving them the shape of a trowel or an artist's spatula. Their eyes are situated on the upper surface, in accordance with their bottom-dwelling lifestyle. They possess two complete dorsal fins, the first one supported by six to 9 strong spines. A platycephalid Flatheads are mostly marine demersal fish, often resting directly on the seabed, sometimes partially buried in sand or mud.

Mioplosus is an extinct genus of percid fish that lived from the early to middle Eocene. Five species of the genus has been described, Mioplosus labracoides is found in the Green River Formation Lagerstätte. Mioplosus has numerous extant relatives in Northern Hemisphere fresh- and brackish water, as well as fossil relatives in Asia, Europe and New Zealand, and may be closely related to the modern-day Pike-perches (genus Sander). Mioplosus are similar to modern Percids, and like them have two dorsal fins, the anterior dorsal fin spiny and the posterior soft-rayed.

Giglioli's Whale Giglioli's Whale, or Amphiptera pacifica, is a purported species of whale observed by Enrico Hillyer Giglioli. It is described to have two dorsal fins, a feature which no known whales have. On September 4, 1867 on board a ship called the Magenta about off the coast of Chile, the zoologist spotted a species of whale which he could not recognize. It was very close to the ship (too close to shoot with a cannon) and was observed for a quarter of an hour, allowing Giglioli to make very detailed observations.

The whale looked overall similar to a rorqual, long with an elongated body, but the most notable difference was the presence of two large dorsal fins about apart. Other unusual features include the presence of two long sickle-shaped flippers and a lack of throat pleats. Another report of a two finned whale of roughly the same size was recorded from the ship Lily off the coast of Scotland the following year. In 1983 between Corsica and the French mainland, French zoologist Jacques Maigret sighted a similar looking creature.

The draughtsboard shark (Cephaloscyllium isabellum) is a species of catshark, and part of the family Scyliorhinidae, so named for its "checkerboard" color pattern of dark blotches. It is endemic to New Zealand, where it is also known as the carpet shark (which usually refers to the entire order Orectolobiformes). This shark typically reaches in length and has a thick body with a broad, flattened head and a capacious mouth. Its two dorsal fins are placed far back on the body, with the first much larger than the second.

Predominantly BCF swimmers often incorporate movement of their pectoral, anal, and dorsal fins as an additional stabilizing mechanism at slower speeds, but hold them close to their body at high speeds to improve streamlining and reducing drag. Zebrafish have even been observed to alter their locomotor behavior in response to changing hydrodynamic influences throughout growth and maturation. In addition to adapting locomotor behavior, controlling buoyancy effects is critical for aquatic survival since aquatic ecosystems vary greatly by depth. Fish generally control their depth by regulating the amount of gas in specialized organs that are much like balloons.

The horn shark (Heterodontus francisci) is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large spines, and a brown or gray coloration with many small dark spots.

Dark edges outline both the caudal and dorsal fins, whereas the pectoral fins have a transparent outline. Their pectoral fins are large and triangular, and extend straight out from the sides of their bodies like airplane wings. They have a venomous spine located at the leading edge of their dorsal fin, which is used in defense. It does not present a serious danger to humans, but can cause painful wounds and has been known to kill harbor seals that ate spotted ratfish (caused by the spine penetrating vital tissue in the stomach or esophagus after the ratfish was swallowed).

Polynemus aquilonaris is a medium- sized species of threadfin which attains a maximum total length of . It has a pointed snout and a dorsal profile which is nearly straight. There are two separate dorsal fins, the first dorsal fin with 8 spines in which the bases of the spines have a similar thickness and the second dorsal fin has a single spine and 15 to 19 soft rays. The anal fin has 3 spines and 11 to 13 soft rays and it has a base that is shorter then the base of the second dorsal-fin base.

Polydactylus plebeius is a medium-sized threadfin which attains a maximum total length of but is more commonly . It has a pointed snout and the dorsal profile of the head is nearly straight. There are two separate dorsal fins, the first containing 8 spines which all have a base of similar thickness and the second dorsal fin has a single spine and 12 or 13 soft rays. The anal fin has 3 spines and 11 or 12 soft rays and has a base with is roughly equal in length to that of the second dorsal fin.

Diving with Frogfish Dive the World 2009 Some of them resemble fish, some shrimp, some polychaetes, some tubeworms, and some simply a formless lump; one genus, Echinophryne, has no esca at all. Despite very specific mimicry in the esca, examinations of stomach contents do not reveal any specialized predation patterns, for example, only worm-eating fish consumed by frogfishes with worm-mimicking esca. If lost, the esca can be regenerated. In many species, the illicium and esca can be withdrawn into a depression between the second and third dorsal fins for protection when they are not needed.

Etheostoma simoterum atripinne reaches sexual maturity in about one year and only survives for a breeding season (maximum life expectancy is about 18 months), which occurs in April to early May. Leading up to the breeding season, males develop bright colors, and by April, all males are deep green to blue-green in color with red-orange dorsal fins and red spots along their bodies. In fact, descriptions of species in the E. simoterum complex of snubnose darters, a group of six teleost freshwater fish species, are based largely on male nuptial coloration. Females do not appear to change in color during breeding.

The flathead gudgeon generally grows to about 8 cm (3.2 in) in length, though large individuals up to 11 or 12 cm (4.5 in) have been recorded. It has a large, flattened head and large mouth, which extends back past the eyes, and two short dorsal fins. The upperparts can be various shades of grey, brown, black, or yellowish, with yellowish underparts. The flathead gudgeon can be distinguished from the dwarf flathead gudgeon (Philypnodon macrostomus) by barred lines on its flanks, larger size (the latter species only reaching 5 cm (2 in) long), and wide gill openings.

The mouth is straight, very narrow, and not highly protrusible, with strong labial folds and a weak groove around the periphery. The nostrils are placed just forward of the mouth and are connected to it by a broad nasoral groove; the nasal flaps are long and fused into a central nasal curtain that overlaps the mouth. There are a pair of large kidney-shaped electric organs at the base of the pectoral fins, visible through the skin. The genera Heteronarce and Electrolux have two large dorsal fins, Narke, Crassinarke, and Typhlonarke have a single dorsal fin, and Temera has none.

A majority of the miniatures were built at 1:25 scale but the Diet building was scaled down to a 1:33 scale to look smaller than Godzilla. The buildings' framework were made of thin wooden boards reinforced with a mixture of plaster and white chalk. Explosives were installed inside miniatures that were to be destroyed by Godzilla's atomic breath while some were sprayed with gasoline to make them burn more easily; others included small cracks so they could crumble easily. Optical animation techniques were used for Godzilla's glowing dorsal fins by having hundreds of cells drawn frame-by-frame.

The pigeye shark or Java shark (Carcharhinus amboinensis) is an uncommon species of requiem shark, in the family Carcharhinidae, found in the warm coastal waters of the eastern Atlantic and western Indo-Pacific. It prefers shallow, murky environments with soft bottoms, and tends to roam within a fairly localised area. With its bulky grey body, small eyes, and short, blunt snout, the pigeye shark looks almost identical to (and is often confused with) the better-known bull shark (C. leucas). The two species differ in vertebral count, the relative sizes of the dorsal fins, and other subtle traits.

The caudal fin is asymmetrical, with a strong lower lobe and a longer upper lobe with a ventral notch near the tip. The dermal denticles are overlapping and bear three horizontal ridges (five in larger individuals) leading to marginal teeth. This species is bronze to gray above and white below, with a white stripe on the flank. A thin black line runs along the leading margins of the dorsal fins, pectoral fins, and the upper caudal fin lobe, as well as the caudal fin trailing margin; the lower caudal fin lobe and sometimes the pectoral fins are also tipped in black.

The blurred lanternshark (Etmopterus bigelowi) is a little-known species of dogfish shark in the family Etmopteridae, found around the world in benthic and pelagic habitats from a depth of to over down. This shark forms the E. pusillus species group with the smooth lanternshark, which are distinguished from other members of its family by having irregularly arranged, flat-topped dermal denticles that give them a "smooth" appearance. Both species are slender-bodied with long heads, two dorsal fins bearing spines, no anal fins, and light-emitting photophores. The blurred lanternshark is larger, reaching or more in length.

A school of rainbow runners The rainbow runner's body is atypical of the jack family, which generally have deep, compressed bodies. The rainbow runner has a subcylindrical, elongated to almost fusiform body, with a long, pointed head and snout and a tapering rear end before the caudal fin emerges. The eyes are relatively small and the teeth are arranged on jaws in villiform bands, with minute teeth also present on the roof of the mouth and tongue. The fish has two dorsal fins, although the posterior rays of the long second fin have separated into a finlet.

The anatomy of a dolphin showing its skeleton, major organs, and body shape Marine mammals have a number of physiological and anatomical features to overcome the unique challenges associated with aquatic living. Some of these features are very species-specific. Marine mammals have developed a number of features for efficient locomotion such as torpedo-shaped bodies to reduce drag; modified limbs for propulsion and steering; tail flukes and dorsal fins for propulsion and balance. Marine mammals are adept at thermoregulation using dense fur or blubber, circulatory adjustments (counter-current heat exchange); and reduced appendages, and large size to prevent heat loss.

The bluebreast darter is small in size, rarely reaching longer than three inches. The snout is a blunt, more rounded than other darters, and its gill covers do not bridge the breast. It is a colorful fish, predominantly olive green with a broad, lighter band that runs adjacent to the dark fringe of the second dorsal and anal fins, reaching the base of the caudal fin. During breeding, though, males tend to be very colorful, usually with orange-tinted dorsal fins, dark red spots along the sides, and the descriptive bright blue breast from which it gets its name.

A large species reaching long, the copper shark is difficult to distinguish from other large requiem sharks. It is characterized by its narrow, hook-shaped upper teeth, lack of a prominent ridge between the dorsal fins, and plain bronze coloration. Feeding mainly on cephalopods, bony fishes, and other cartilaginous fishes, the copper shark is a fast-swimming predator that has been known to hunt in large groups, utilizing their numbers to their advantage; however for most of the time they remain solitary. Off South Africa, this species associates closely with the annual sardine run, involving millions of southern African pilchard (Sardinops sagax).

It was covered in scales that were cubical in shape. It also had fewer spines than many of its relatives. Each of the paired pectoral and pelvic fins had a spine, as did the single anal and dorsal fins, giving it a total of just six, less than half that of many other species. A fossil discovered near Hamilton, Kansas in the Upper Carboniferous Hamilton Formation, and published in 2014 as Acanthodes bridgei was so well-preserved that traces of its eye tissue were sufficient to establish that Acanthodes had both rod and cone photoreceptor cells, and thus profited from color vision.

Prague Vltava fish exhibition The young, free-swimming pike feed on small invertebrates starting with daphnia, and quickly move on to bigger prey, such as the isopods asellus or gammarus. When the body length is , they start feeding on small fish. A pike has a very typical hunting behavior; it is able to remain stationary in the water by moving the last fin rays of the dorsal fins and the pectoral fins. Before striking, it bends its body and darts out to the prey using the large surface of its caudal fin, dorsal fin, and anal fin to propel itself.

The outer pair of mandibular barbels is two to three times the length of the inner pair; and the outer pair with moderately long, slender branches and the inner pair with secondary branches present. The front edges of the dorsal fins and the pectoral fins of Syntontis species are hardened into stiff spines. In S. depauwi, the spine of the dorsal fin is about times the length of the head, nearly straight, sharp-edged in the front and serrated on the back. The remaining portion of the dorsal fin is made up of seven branching rays.

The herring scad is an ovate shape, commonly blue green above and silver belowThe herring scad has a body profile very similar to other members of the genus Alepes, having a strongly compressed, ovate body. The ventral and dorsal profiles of the fish are almost evenly convex, joined anteriorally by a pointed snout. There are two separate dorsal fins, the first containing 8 spines while the second has a single spine followed by 24 to 27 soft rays. The anal fin consists of two anteriorally detached small spines followed by a single spine connected to 20 to 23 soft rays.

The whale appears dark from the top while its flippers and tail, the sides and underside appear partially white and are noticeable when they are beginning dive as are their small dorsal fins. These white markings on their flukes are completely unique, each working as a personal fingerprint that scientists use to identify them. These whales are air breathers, rising to the surface every thirty or so minutes. Their exhale can rise up to 15 feet into the air, clocking at a speed of 300 mph(the human sneeze at its fastest is about 100 mph).

The ocellated electric ray or bullseye electric ray (Diplobatis ommata) is a species of electric ray in the family Narcinidae, native to the shallow inshore waters of the eastern central Pacific from the Gulf of California to Ecuador. Reaching in length, this species has a rounded pectoral fin disc and pelvic fins with convex margins. Its short and thick tail bears two dorsal fins and terminates in a triangular caudal fin. The ocellated electric ray is named for the distinctive large eyespot on the middle of its disc, consisting of a black or yellow center surrounded by concentric rings.

The yellowtail barracuda has an elongated body with two well separated dorsal fins, the anterior dorsal fin has five spines with the first spine being the longest. The origin of the second dorsal fin is positioned slightly in front of that of the anal fin. The pelvic fin is located below the tip of the pectoral fin, which in turn is positioned in front of the origin of the anterior dorsal fin. The large head is slightly flattened towards the rear and bears a large eye, pointed snout and long jaws, with a prognathic lower jaw.

The length of the anal fin base exceeds the distance between the anal and pelvic fins, and is comparable to the distance between the dorsal fins. The caudal fin is short and low, with a small lower lobe and a ventral notch near the tip of the upper lobe. The body and fins are entirely covered by minute, overlapping dermal denticles; each has an ovoid crown with a horizontal ridge leading to a marginal cusp. There are distinctive crests of enlarged, spiny denticles along the anterior half of the caudal fin upper margin, and beneath the caudal peduncle.

The fish of the genus are large, powerful fishes that look very similar to a number of other large jacks, with the main difference being the profile of the head and the characteristic long filamentous anal and dorsal fins displayed by juveniles of these species. They are generally a silver colour, with pale green to hyaline fins. A. indica is the largest of the genus, growing to a reported 165 cm and 25 kg in weight. The genus has a circum-tropical distribution, with adults generally restricted to reefs in coastal areas down to 100 m, while juveniles are often pelagic.

P. gibbiceps, a crest exists over the back of the skull that was used to distinguish Glyptoperichthys species from Pterygoplichthys species. Pterygoplichthys can be differentiated from most other loricariids due to their large dorsal fins with 9 or more (usually 10) dorsal fin rays, which gives them their common name "sailfin catfish". These fish have rows of armour plating covering the body; the abdomen is almost completely covered in small plates. Other characteristics of members of this genus include an underslung suckermouth, evertable cheek plates, adipose fin present, and an enlarged stomach connected to the dorsal abdominal wall by a connective tissue sheet.

The sicklefin lemon shark (Negaprion acutidens) or sharptooth lemon shark, is a species of requiem shark belonging to the family Carcharhinidae, widely distributed in the tropical waters of the Indo-Pacific. It is closely related to the better-known lemon shark (N. brevirostris) of the Americas; the two species are almost identical in appearance, both being stout-bodied sharks with broad heads, two dorsal fins of nearly equal size, and a plain yellow- tinged coloration. As its common name suggests, the sicklefin lemon shark differs from its American counterpart in having more falcate (sickle-shaped) fins.

Like other members of its family, it has a long anal fin, a minute caudal fin, no pelvic or dorsal fins, and an electroreceptive dorsal appendage that originates about halfway along the back. There are 155-168 anal fin rays, 14-15 pectoral fin rays, and 16-17 caudal fin rays. The scales are large and diamond-shaped, with 6-8 rows above the lateral line but not reaching the upper surface of the head and body. Virtually unpigmented aside from tiny chromatophores speckling the bottom of the head and branchiostegal membranes, P. amazonensis is uniformly white-pink with translucent fins.

It has 46-60 upper tooth rows and 43-54 lower tooth rows; each tooth is small, with a narrow central cusp and a pair of lateral cusplets. Unusually for a shark, dental sexual dimorphism occurs, with the front teeth in males being greatly enlarged. The two dorsal fins are small and about equal in size; the first is positioned between the pectoral and pelvic fins, and the second over the anal fin. The dorsal margin of the caudal fin is smooth and lacks a notch (precaudal pit) at its base; the lower caudal fin lobe is virtually absent.

The sicklefin weasel shark (Hemigaleus microstoma) is an uncommon species of ground shark in the family Hemigaleidae. It is native to southern India, southern China, and parts of Southeast Asia, living in shallow waters down to a depth of . This lightly built shark is characterized by its very short mouth, broad upper teeth with serrations only on the trailing edge, and strongly sickle-shaped fins with obvious white tips on the two dorsal fins. It is light grey or bronze in colour, often with small white blotches on its sides; it reaches a maximum known length of .

The caudal fin is marked with a totral of 11-15 bars with 4-6 reddish brown bars on the upper lobe and 6-9 red-brown or grey bars on the lower part of the lower lobe which extend to form a broad brown or dark grey stripe along middle of lobe. There are also 3-4 brownish-red or grey bars on inner, upper half of lower lobe, these bars are nornmally visible on preserved specimens. The dorsal fins have a total of 7 spines and 9 soft rays while the anal fin has a single spine and 7 soft rays. This fish attains a standard length of .

The body plan of the combtooth blennies is archetypal to all other blennioids; their blunt heads and eyes are large, with large continuous dorsal fins (which may have three to 17 spines). Their bodies are compressed, elongated, and scaleless; their small, slender pelvic fins (which are absent in only two species) are situated before their enlarged pectoral fins, and their tail fins are rounded. As their name would suggest, combtooth blennies are noted for the comb-like teeth lining their jaws. By far the largest species is the eel-like hairtail blenny at 53 cm in length; most other members of the family are much smaller.

It is possible to distinguish species within the genus from each other by looking at the pore patterns and numbering and patterns of the anal and dorsal fins. Fish within this genus have a slender body with a slender, depressed head and a short rounded snout, tubular nostrils on each side of the head that are free of a dermal flap and large eyes with narrow bony interorbit. They have a united gill membrane (no isthmus) fused opposite of the fourth pectoral ray, four gill arches with rakers and filaments; rakers are short and pointed. They have a pore system, but it is only on the head of the fish.

The swim bladder has a short, blunt anterior median projection with no posterior projection. The southern school whiting has a body colour of creamy brown to rusty above, before an abrupt transition to a silvery white below, with a brilliant longitudinal silver band separating the colours. A narrow rusty brown horizontal band is positioned above the silver band, with irregular red-brown oblique blotches and broken stripes positioned on the back and upper sides, much like Sillago maculata. The dorsal fins have rows of rusty brown or red-orange spots, the anal fins are yellow to hyaline in colour, while all other fins are pale cream, white or hyaline in appearance.

The royal threadfin is a medium-sized threadfin species reaching a maximum total length of , although a more normal length is . It has two separate dorsal fins, the first dorsal fin has 8 spines and the second dorsal fin has a single spine and 14 or 15 soft rays. The anal fin contains 3 spines and 24 to 30 soft rays, with a base which is longer than that of the second dorsal-fin. The pectoral fin has 14 to 16 unbranched rays and is 30% to 42% of the fish's standard length with its tip extending to or just short of the centre of the base of the anal fin.

The Pacific blue-eye (Pseudomugil signifer) is a species of fish in the subfamily Pseudomugilinae native to eastern Australia. Described by Austrian naturalist Rudolf Kner in 1866, it comprises two subspecies that have been regarded as separate species in the past and may be once again with further study. It is a common fish of rivers and estuaries along the eastern seaboard from Cape York in north Queensland to southern New South Wales, the Burdekin Gap in central-north Queensland dividing the ranges of the two subspecies. A small silvery fish averaging around in total length, the Pacific blue-eye is recognisable by its blue eye ring and two dorsal fins.

The Balao halfbeak is similar in appearance to its relative the ballyhoo (H. brasiliensis). The main difference between the two is that the distance from the nares to the base of the pectoral fin is greater than the length of the ballyhoo's pectoral fin, while that difference is less than the length of the Balao halfbeak's pectoral fin They have no spines on fins, but do have 11-15 rays of their dorsal fins and 10-13 rays on their anal fins. Balao halfbeak have blue-gray skin on their backs, while their undersides are silver or white. The longest recorded Balao halfbeak was 40 cm long.

Polynemus multifilis is a medium-sized species of threadfin which attains a maximum standard length of . It has a pointed snout and the dorsal pofile of the head is almost straight, There are two separate dorsal fins, the first dorsal fin contains 8 spines which are all of a similar thickness at their bases and the second dorsal fin has a single spine and 14-16 soft rats. The anal fin contains 3 spines and 11 to 13 soft rays and its base is shorter than that of the second dorsal fin. The pectoral fin has 14-16 unbranched soft rays and its tip reaches the origin of the anal fin.

A migrating smooth hammerhead swimming with its dorsal fin exposed Adult smooth hammerheads are either solitary or form small groups. They may come together in great numbers during their annual migrations; schools of over a hundred juveniles under long have been observed off the eastern Cape of South Africa, and schools thousands strong have been reported off California. During hot summer weather, they can be seen swimming just below the surface with their dorsal fins exposed. Young smooth hammerheads are preyed upon by larger sharks such as the dusky shark (Carcharhinus obscurus); adults have been observed being consumed by killer whales (Orcinus orca) off New Zealand.

The Pacific jack mackerel is very similar to all other members of Trachurus and a number of other carangid genera, having an elongated, slightly compressed body with both the dorsal and ventral profiles of the body having the same degree of curvature. It is a medium- to large-sized fish, growing to a maximum known length of 81 cm (32 in), although more common at below 55 cm. The two separate dorsal fins are composed of eight spines and one spine followed by 31 to 35 soft rays, respectively. The anal fin is composed of two spines anteriorly detached followed by one spine connected to 26 to 30 soft rays.

The prickly shark (Echinorhinus cookei) is one of the two species of sharks in the family Echinorhinidae (the other one is the bramble shark), found in the Pacific Ocean over continental and insular shelves and slopes, and in submarine canyons. Bottom-dwelling in nature, it generally inhabits cool waters deep, but it also frequently enters shallower water in areas such as Monterey Bay off California. This stocky, dark-colored shark grows up to long, with two small dorsal fins positioned far back on its body and no anal fin. It is characterized by a dense covering of thorn-like dermal denticles, hence its common name.

There is a broken dark line which frequently runs from the lower mandible through the middle of the eye, and proceeding to the upper part of the gill cover. The males are brighter and the blue line sare more obvious, continuing on to the bases of both the dorsal and anal fins. Like other pupfish this species is sexually dimorphic and the males have more extravagant fins than the females with added extensions on the anal and dorsal fins while their tail can be washed with blue. The females are plainer and often display mottling or splotching along the centre line of the body.

As general mullet, fish they have a terminal mouth with thick lips, 2 dorsal fins, a lunate homocercal caudal fin (upper lobe and lower lobe are equal length) and do not have a lateral line organ, which is usually used for detecting changes in their surroundings. The cycloid (smooth outer edge) scales of the sand grey mullet fish are thin, flexible and overlapping with a mix of silver and grey color scheme. They are easily identified by their bright yellow eyes. They have a skeleton made of bone and have a streamline body shape for body undulations that allows them to be fast swimmers.

The lower jaw is similar, having two rows of short conical teeth in the front of the jaw changing to one row of blunter teeth further back. There are two separate dorsal fins, the first containing eight weak spines while the second consists of a single spine followed by 23 to 26 soft rays. The anal fin has two detached spines anterior to the main section, which consists of a single spine followed by 19 to 22 soft rays. The upper caudal fin lobe is larger than the lower lobe, whilst the pelvic fin is quite small in comparison to those of other carangids.

The pyjama shark or striped catshark (Poroderma africanum) is a species of catshark, and part of the family Scyliorhinidae, endemic to the coastal waters of South Africa. This abundant, bottom-dwelling species can be found from the intertidal zone to a depth of around , particularly over rocky reefs and kelp beds. With a series of thick, parallel, dark stripes running along its stout body, the pyjama shark has an unmistakable appearance. It is additionally characterized by a short head and snout with a pair of slender barbels that do not reach the mouth, and two dorsal fins that are placed far back on the body.

In areas where resident pilot whale populations are seen near the coast, such as those off the Canary Islands, Madeira, and Hawaii, they can be studied using photo-identification. This technique helps researchers identify unique markings and scars on the whales’ dorsal fins, which are used to recognize individuals from photographic surveys to monitor movements and life histories over time. Other research techniques including satellite tagging, acoustics, and genetics to learn about the species' long-range movements, genetic diversity and social behaviour. However, there have been few long-term studies focused on this species, and data is spotty for many of the small local populations.

The Aden Gulf torpedo or Aden torpedo (Torpedo adenensis) is a poorly known species of electric ray in the family Torpedinidae, seemingly endemic to the eastern Gulf of Aden, near the coast of Yemen. Growing to long, this species has a nearly circular pectoral fin disc and a short, thick tail with two dorsal fins and a well-developed caudal fin. It is characterized by its reddish dorsal coloration, which in contrast to related species lacks any additional markings. The International Union for Conservation of Nature (IUCN) has assessed the Aden Gulf torpedo as Endangered, citing its extremely small range and the intensive shrimp trawling that occurs in the region.

E. lineatus has a total of 10-15 spines in its dorsal fins with the anterior spines of the first dorsal fin being much taller than the middle spines which gives this fin a concave outline. The anal fin has 11 - 12 soft rays and it has a vertebra count of 37. Its body is almost entirely scaleless except for the lateral line and a "corselet" and there is no swim bladder. It is generally iridescent blue in colour with black markings on its back made up of 3 to 5 horizontal stripes, as well as a variable amount of black or dark grey spots above the pelvic fins.

The Atlantic threadfin is a medium-sized species of threadfin which grows to a maximum total length of , although most fish have a total length of around . It has a pointed snout and an almost straight dorsal profile on its head. There are two separate dorsal fins, the first dorsal fin contains 8 spines in which the bases of each spine is a similar thickness to the others, and the second dorsal fin has a single spine and 11 to 13 soft rays. The anal fin has 3 spines and 12 to 14 soft rays, The base of the anal fin is longer than that of the second dorsal fin.

Unlike many species of pelagic spawning fish the common dragonet spawns as a pair. They have quite an elaborate courtship in which the male approaches the female, spreading his pectoral fins and erecting both dorsal fins, displaying their colours, while simultaneously repeatedly raising his head and opening his mouth very wide. If the female responds to this display the male becomes more excited and eventually the pair swim, with the female resting on the pectoral fins of the male, vertically to the surface where the eggs and milt are released between their bodies to be fertilised. After fertilisation the eggs drift away in the current.

An angler's catch of shadow trevally The shadow trevally is similar in form to a number of other jacks in the family Carangidae, having an almost ovate, strongly compressed body. It is fairly large fish, growing to a maximum known length of 85 cm and a recorded weight of 2.6 kg. The dorsal profile is strongly convex, while the ventral profile is less so, even tending to be concave between the snout and the anal fin, while the nape is elevated and almost straight in profile. There are two separate dorsal fins, the first consisting of 8 spines and second of a single spine and 17 to 19 soft rays.

Remora front dorsal fins have evolved to enable them to adhere by suction to smooth surfaces and they spend their lives clinging to a host animal such as a whale, turtle, shark or ray. It is probably a mutualistic arrangement as the remora can move around on the host, removing ectoparasites and loose flakes of skin, while benefiting from the protection provided by the host and the constant flow of water across its gills. Although it was initially believed that remoras fed off particulate matter from the host's meals, this has been shown to be false; in reality, their diets are composed primarily of host feces.

The grooved mullet has a total of five spines in its dorsal fins and eight or nine soft rays, the anal fin has three spines and eight or nine soft rays. The anal fin and the lower lobe of the caudal fin are coloured whitish or greyish. The body is coated in ctenoid scales apart from the scales in front of the anterior dorsal fin which are cycloid, extending to the front nostril or slightly beyond it. Its scales are small and numerous and there are 33–41 scales in a longitudinal series, not including those on the caudal peduncle, and 11–14 scale rows between pelvic and anterior dorsal fin.

Mouth of a Port Jackson shark showing teeth and crushing plate Two Port Jackson sharks, demonstrating "harness" feature Port Jackson sharks can grow up to long and are similar to others of their genus, bearing a broad, blunt, flat head, an anal fin, and crests above its eyes. However, the species possesses characteristics that make them easily identifiable, such as their teeth and the harness-like markings which run for a majority of their body length. These markings run from their eyes to their first dorsal fin and then across the rest of their bodies. Both dorsal fins are close to equal size, each with a spine at the foremost edge.

The tiger shark is a member of the order Carcharhiniformes, the most species-rich order of sharks, with more than 270 species also including the small catsharks and hammerhead sharks. Members of this order are characterized by the presence of a nictitating membrane over the eyes, two dorsal fins, an anal fin, and five gill slits. It is the largest member of the Carcharhinidae family, commonly referred to as requiem sharks. This family consists of mostly slender but powerful mid- to large-sized sharks and includes some other well-known sharks, such as the blue shark (Prionace glauca), lemon shark (Negaprion brevirostris), and bull shark (Carcharhinus leucas).

It has large pectoral and first dorsal fins, tiny pelvic, second dorsal, and anal fins, and a crescent-shaped caudal fin. The most distinctive features of this species are its three-cusped teeth, the white blotch at the aft base of its first dorsal fin, and the two pairs of lateral keels on its tail. The porbeagle is an opportunistic hunter that preys mainly on bony fishes and cephalopods throughout the water column, including the bottom. Most commonly found over food-rich banks on the outer continental shelf, it makes occasional forays both close to shore and into the open ocean to a depth of .

Yellowtail scad from Palau The yellowtail scad has a body profile quite similar to that of the other fish often called 'scad' from the genera Decapterus and Trachurus, having a moderately compressed, oval-shaped body. The dorsal and ventral profiles of the fish are nearly evenly convex, with the two lines intersecting at the pointed snout. There are two separate dorsal fins; the first consisting of eight moderately high spines and the second of a single spine followed by 22 to 25 soft rays. The anal fin consists of two anteriorly detached spines followed by a single spine attached to 18 to 21 soft rays.

The males also have higher values of the proportions of the dorsal fins, and the superior lobe of their caudal fin. The females have a wider trunk (main part of the body), this is because they have to accommodate all of the embryos that they hold (Rolim 2015). Males have a greater proportion of their electric organs than females, this may be another example of resource allocation in this species since the females have to use more energy to produce nutrients for the embryos (Macesic 2008). Development Although little is known about this species’ life cycle, scientist do know that they have slow growth the birth is viviparous (Marinsek 2017).

The yellowfin whiting has a similar body profile to most other Australian sillaginids, with colour and swimbladder morphology the simplest identifying features. It is one of the largest members of the Sillaginidae, growing to a known maximum known length of 42 cm and a weight of 860 g. The body is elongate and compressed, with the dorsal profile more arched than the ventral. The mouth is small and oblique, having a broad band of villiform teeth in each jaw. There are two slightly separated dorsal fins, the first consisting of 10 to 12 spines and the second of 1 spine followed by 19 to 22 soft rays.

However, dolphins in captivity may not show the same behavior that they do in their natural environment, where they have been reported to hold the oars of the fishermen, rub against the boat, pluck underwater plants, and play with sticks, logs, clay, turtles, snakes, and fish. They are slow swimmers; they commonly travel at speeds of but have been recorded to swim at speeds up to . When they surface, the tips of the snout, melon and dorsal fins appear simultaneously, the tail rarely showing before diving. They can also shake their fins, and pull their tail fin and head above the water to observe the environment.

The position of the gill openings separates them from the superficially similar, but generally much smaller (up to long) sawsharks, where the slits are placed on the side of the neck. Unlike sawfish, sawsharks also have a pair of long barbels on the rostrum ("saw"). Sawfish have two relatively high and distinct dorsal fins, wing-like pectoral and pelvic fins, and a tail with a distinct upper lobe and a variably sized lower lobe (lower lobe relatively large in Anoxypristis; small to absent in Pristis sawfish). The position of the first dorsal fin compared to the pelvic fins varies and is a useful feature for separating some of the species.

Thymallus species are distinguished from other members of the salmon family by their larger scales, their small mouths with teeth on the maxillary bone, and most striking of all, their showy, sail-like dorsal fins. This fin is longer in males and highly colourful, with spots of red, orange, purple or green. The body is also colourful; the dorsal surface is a dark purplish to bluish black or gray, grading to dark blue or silver gray on the flanks and gray or white on the belly. The body is further decorated with a smattering of small dark spots; these are much more numerous in juveniles.

Merluccius merluccius Merluccius merluccius is a slim-bodied fish with a large head and large jaws on which are set a number of large curved teeth, the lower jaw has two rows of teeth and the upper jaw has one row. The inside of the mouth and the branchial cavity are black. The body is at its widest just behind its head. It has two dorsal fins; the first is triangular in shape, high with a short base, while the second is long, nearly the same length as the anal fin, and both the second dorsal fin and the anal fan have a slightly convex profile.

Like other members of Alepes, it has an adipose eyelid which is well developed only on the posterior section of the eye. The dorsal fin is split into two sections like in all of the Carangidae, the first with 7 or 8 spines and the second with one spine followed by 23 to 26 soft rays. The anal fin consists of two detached spines followed by a single spine and 18 to 21 soft rays, with both the anal and dorsal fins have a low profile. The pectoral fin is falcate and extends to beyond the junction of the curved and straight sections of the lateral line.

Ectomesenchyme (also known as mesectoderm):Kalcheim, C. and Le Douarin, N. M. (1998). The Neural Crest (2nd ed.). Cambridge, U. K.: Cambridge University Press. odontoblasts, dental papillae, the chondrocranium (nasal capsule, Meckel's cartilage, scleral ossicles, quadrate, articular, hyoid and columella), tracheal and laryngeal cartilage, the dermatocranium (membranous bones), dorsal fins and the turtle plastron (lower vertebrates), pericytes and smooth muscle of branchial arteries and veins, tendons of ocular and masticatory muscles, connective tissue of head and neck glands (pituitary, salivary, lachrymal, thymus, thyroid) dermis and adipose tissue of calvaria, ventral neck and face Endocrine cells: chromaffin cells of the adrenal medulla, glomus cells type I/II.

The second dorsal fin measures about 67-77% as tall as the first and is similar in shape; there is no midline ridge between the dorsal fins. The anal fin is almost as large as the second dorsal fin and lies slightly behind; it has a deep notch in the posterior margin. The caudal fin is asymmetrical; the lower lobe is narrow and well-developed, while the upper lobe has a gently convex upper margin and a prominent notch in the ventral margin near the tip. The body is covered by small, overlapping oval-shaped dermal denticles bearing three or five horizontal ridges leading to marginal teeth.

The nostrils are just forward of the mouth and connected to it by a broad groove; the nasal flaps are short, but merged into a broad nasal curtain that overlaps the mouth. The small teeth have a single moderate cusp; the teeth and tooth bands are exposed when the mouth is closed (except in Diplobatis). Two prominent dorsal fins of roughly equal size and a large caudal fin are present. Numbfishes vary in color from whitish or yellowish to brownish, grey-brown, greenish, reddish, or black above, either plain or with small to large spots, blotches, bars or lines, sometimes forming complex eye-shaped spots or ocelli on the pectoral fins.

The cranial sensory system of the family is well developed above and laterally, with the lower jaw having a pair of small pores behind which is a median pit containing a pore on each side. On each side of the elongate head the operculum has a short sharp spine. They have two true dorsal fins; the anterior one supported by 10 to 13 spines while the long rear one is held up by a single leading spine followed by 16 to 27 soft rays. The anal fin is similar to the second dorsal fin, having two small slender spines followed by 14 to 26 soft rays.

Its fins vary from colourless to blackish-grey and the dorsal fins have between one and three dark stripes with a yellow or orange background colour. The margins of the fin are frequently fin margins yellow and the caudal fin is marked with many dark spots which are arranged in irregular bands. The body of Gobiomorphus coxii is nearly cylindrical and tapers towards the tail, the head is large with a blunt, round snout and the quite small eyes are positioned high on the head. The mouth is relatively large, oblique and turned upwards with the lips ending lust below the front part of the eyes.

Two separate dolphins appearing as if they're one dolphin by perspective The rhinoceros dolphin (Delphinus rhinoceros or Cetodipteros rhinoceros) is a purported species of dolphin – or dolphin-like whale – said to have an additional dorsal fin on or near the head, reminiscent of a rhinoceros horn. Jean René Constant Quoy and Joseph Gaimard allegedly discovered this dolphin off the coast of the Sandwich Islands and New South Wales. It supposedly possesses two dorsal fins, much like Giglioli's Whale. One is near the head, where the neck would be on terrestrial animals, and the other is farther back than the dorsal fin of any other dolphin.

The pelvic fins are much smaller, and bear claspers in males; in G. murinus and G. nipponensis, the pelvic fin inner margins are partially fused to form an "apron" over the base of the claspers. The anal fin is elongated and much larger than the pelvic and dorsal fins; its position relative to the pelvic and caudal fins varies from very close to well-spaced. The caudal peduncle can be nearly cylindrical to laterally compressed, depending on species. The caudal fin comprises more or less a quarter of the total length, and is low with a small lower lobe and a ventral notch near the tip of the upper lobe.

Southern right whale dolphins can be easily distinguished from other cetacean species within their range as they are the only dolphins without dorsal fins in the Southern Hemisphere. They have streamlined and graceful bodies, a single blowhole and a short and defined beak, possessing between 39 and 50 teeth per row. A sharp dividing line separates the black dorsal part from the white ventral part of the body, running from the tail stock forward, dipping down to the flipper insertion and sweeping back up, below the eyes, to cross the melon between the blowhole and snout crease. Younger individuals can be grey/brownish dorsally but develop adult coloration within the first year.

The Barameda has an extremely elongated and thick body typical of Carboniferous rhizodonts, built for powerful swimming, and out- powering any prey larger than itself. It is covered with durable cosmoid scales all along its body, with thick bony plates covering its head and operculum (gill flaps), a tightly fused Skull roof, and extremely prominent, sharp fangs, devoid of serrations or cutting edges. It had an advanced lateral line system that was elaborated along its pectoral girdle, larger pectoral fins than pelvic fins, with deeply over-lapping scales along its fins, turning the pectoral fin into a large paddle. Its anal fins and secondary dorsal fins form a functional part of its tail.

The Philippines angelshark (Squatina caillieti) is a species of angelshark, family Squatinidae, known only from a long immature female caught in the Philippines, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the spiracles, which are more widely spaced than the eyes and bear papillae (nipple-shaped structures) on the posterior inner rims, and the relative positions of the two dorsal fins. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli ("eyespots") on its fins.

Coloration in life is typically a highly lustrous silver, with younger dories covered in a number of randomly placed dark, dusky spots. These spots tend to fade with age; the largest (and oldest) specimens have only one dark spot, located roughly central on the flanks. In the cape dory (Zeus capensis) this spot is located just below the junction of the spinuos and soft dorsal fins; in the John dory the spot is central and surrounded by a yellow ring, with the body also covered in cloud-like splotches of muddy sepia. Zeus capensis and Z. faber are tied as the largest dory species at a maximum 90 centimetres total length, with the other three species only slightly smaller.

A P. tetrazona close to sexual maturity The tiger barb usually attains sexual maturity at a body length of in total length, or at approximately six to seven weeks of age. The females are larger with a rounder belly and a mainly black dorsal fin, while the males have a bright, red nose with a distinct red line above the black on their dorsal fins. The egg-layers tend to spawn several hundred eggs in the early morning in clumps of plants. On average, 300 eggs can be expected from each spawn in a mature broodstock population, although the number of eggs released will increase with the maturity and size of the fish.

The anal fin has three spines and seven soft rays. The caudal fin is rounded. The colour of the head and body is white to pink to reddish with a ref iris and the dorsal part of the head and nape being red. There is a white band which runs along the middle of the head starting at the top lip and ending at the 2nd spine in the dorsal fin and another wide red bar which runs from the soft rayed portion of the dorsal fin vertically on the body onto the anal fin> The anal and dorsal fins have white edges, the pelvic fins are white while the caudal fin is red with a white posterior margin.

They have tiny conical teeth on the mandibles and on the vomer and palatine bones. There are two dorsal fins an anterior dorsal fin with 6 slender spines and a posterior dorsal fin with 13 to 18 soft rays, the pelvic fins have 1 weak spine and 5 branched rays and these are positioned anteriorly to the pectoral fins with their bases widely separated. The anal fin has only 15 to 25 soft rays and the pectoral fins have between 20 and 28 rays. They body is covered in ctenoid scales and the lateral line curves underneath the anterior dorsal fin to below the middle of the flank with the 2 or 3 scales nearest the head being keeled.

Commensal fish: a remora holds on to its host with a sucker-like organ (detail inset) Some teleosts are parasites. Remoras have their front dorsal fins modified into large suckers with which they cling onto a host animal such as a whale, sea turtle, shark or ray, but this is probably a commensal rather than parasitic arrangement because both remora and host benefit from the removal of ectoparasites and loose flakes of skin. More harmful are the catfish that enter the gill chambers of fish and feed on their blood and tissues. The snubnosed eel, though usually a scavenger, sometimes bores into the flesh of a fish, and has been found inside the heart of a shortfin mako shark.

The terminal soft rays of both the anal and dorsal fins are nearly twice as long as the penultimate rays, forming distinctive finlet-like structures, although are still attached to the main fin structure by interradial membranes. The lateral line is slightly arched anteriorally, with the intersection of the curved and straight section occurring below the sixth to eighth dorsal soft ray. The curved section contains between 39 and 57 scales, while the straight section has no to 10 scales and 36 to 49 scutes. Another of the major distinguishing features of the species is an adipose eyelid which fully encloses the eye except for a small vertical slit over the pupil.

Physical Description They are small to moderate sized, not very big, they can get to only about 45 centimeters in total length (Vianna 2009). The shape of their body is an oval shape, with two dorsal fins that are around the same size (Wosnick 2018), the caudal fin is shaped like a triangle and there is no spine on the caudal fin on this ray, unlike some other species. On the dorsal side of their body they have a brown coloration and a white coloration on their ventral side. They have more of an elongated/protruding body size, they aren't very short or rounded, this helps to differentiate them from other ray species (Olfers 1831).

An anglers catch of brownback trevallyThe brownback trevally is a relatively small species of carangid, growing to a maximum recorded length of 25 cm, but is much more common at lengths less than 16 cm. The species has a similar body profile to other trevallies in the same genus, having an elongate, compressed form with the dorsal and ventral profiles approximately equal in convexity. The dorsal fin is in two parts, the first consisting of 8 spines while the second has 1 spine and 21 to 24 soft rays, with both dorsal fins of approximately equal height. The anal fin has two anteriorly detached spines followed by 1 spine and 18 to 20 soft rays.

240pxThe shrimp scad is can grow to a large size compared to other scads, reaching a maximum known length of 40 cm, but more often seen around 25 cm. The shrimp scad has a body profile very similar to other scads and some other carangids, with an oblong, compressed body and dorsal and ventral profiles which are almost evenly convex. The snout is pointed and the eye diameter is nearly equal to the snout length, with an adipose eyelid well developed on the posterior half of eye. There are two moderately high, separate dorsal fins, the first of which has eight spines, while the second has a single spine followed by 23 to 25 soft rays.

Longman's beaked whales look rather similar to both mesoplodont beaked whales and bottlenose whales, which led to a great deal of taxonomic confusion. The Maldives female had a robust body like the bottlenoses, although this may be a distortion, since the less- decomposed female specimen from Japan had a laterally compressed body typical of Mesoplodon. The juvenile specimens have a very short beak similar to a bottlenose whale, but the adult females seen so far have had rather long beaks sloping gently into a barely noticeable melon organ. Additionally, the dorsal fins of adult specimens seem unusually large and triangular for beaked whales, whereas in juveniles they are rather small and swept back.

The Atlantic torpedo is aplacental viviparous: the developing embryos are sustained by yolk, which is later supplemented by protein and fat-enriched histotroph ("uterine milk") produced by the mother. Females have two functional ovaries and uteruses, and a possibly biennial reproductive cycle. After a year-long gestation period, females bear up to 60 pups during the summer; the litter size increases with the size of the female. When the embryo is long, it has a pair of deep notches at the front of the disc marking the origin of the pectoral fins, and the curtain of skin between the nostrils has not yet developed; on the other hand, the eyes, spiracles, dorsal fins, and tail have reached adult proportions.

The back is pinkish-red in colour contrasting with the white belly, from which it is separated by single longitudinal yellow stripe which runs from the operculum to the caudal fin peduncle. The dorsal fins are yellow in colour with 3 parallel red bars while the pectoral fin is a similar colour but lacks markings and the pelvic fin is colourless. The upper lobe of caudal fin is whitish and has 5 or 6 black diagonal bars while the lower lobe is unmarked except for the hind margin which is black as the second bar of the upper lobe extends along it. They can grow to 25 cm but are more usually 10–15 cm.

Supernumerary dorsal fins are apparently a genuine mutation; however, none have turned up a considerable distance from where the dorsal fin should be positioned, let alone on the head. Raynal and Sylvestre (1991) argued that since Quoy and Gaimard observed multiple individuals exhibiting the morphology, a distinct species, Cetodipterus rhinoceros, would be more probable than a pod of disfigured individuals. Another argued hypothesis is that that pod was part of an inbred population, which led to the mutation. Another possibility is that Quoy and Gaimard observed specimens which were neither deformed nor members of an unknown species or population, but rather misidentified a pair of beaked whales that, by perspective, appeared to be one single creature.

Its underside is smooth and its dorsal surface is densely covered with prickly scales. Two or three pairs of distinctive scapular thorns are on each shoulder, usually arranged in a triangle, and a row of 24-29 median thorns occur along the back, flanked by a row of smaller lateral thorns on the tail. The tail of the shorttail skate is relatively short. Sexual dimorphism in shorttail skates is present in pelvic fin structure that the males modify to act as copulatory claspers, as well as alternate disc lengths, horizontal diameter of the orbit, height of the tail at the pelvic fin tips, length of the third gill slit, and distances from the center of the anus to the first and second dorsal fins.

Silver-banded whiting for sale in the Philippines as 'asuhos' The silver-banded whiting shows the same basic body profile as the rest of the members of the genus Sillago, possessing an elongate, slightly compressed body tapering toward the terminal mouth, with two apparent dorsal fins. The species has a more curved ventral profile than most of its relatives however, and within its known range, this and the silvery band may be enough to identify it in the field. More definitive characteristics are the dorsal and anal fins, with the first dorsal fin possessing 11 spines while the second dorsal contains one spine and 17 or 18 soft rays posterior to the spines. The anal fin has two spines followed by 17 soft rays.

The name was a reference to the town in which he was first spotted. After several months, the animal moved north to a local beach, where he frequently got close to bathers and interacted with them. Tião quickly became popular and on occasion over thirty people would be in the water with the dolphin at the same time, sometimes trying to grab hold of his pectoral and dorsal fins to have him drag them through the water. Harassment of the dolphin started to take ever more serious forms, from people attempting to restrain the dolphin to have their picture taken with him, to trying to stick an ice cream cone in his blowhole and attempting to pour beer into his mouth.

Propulsive forces in MPF swimming, on the other hand, are generated by multiple fins located on either side of the body that can be coordinated to execute elaborate turns. As a result, MPF swimming is well adapted for high maneuverability and is often seen in smaller fish that require elaborate escape patterns. It is important to point out that fish do not rely exclusively on one locomotor mode, but are rather lomotor "generalists," choosing among and combining behaviors from many available behavioral techniques. In fact, at slower speeds, predominantly BCF swimmers will often incorporate movement of their pectoral, anal, and dorsal fins as an additional stabilizing mechanism, but hold them close to their body at high speeds to improve streamlining and reducing drag.

Eviota guttata has a total of 6–7 spines in its dorsal fins and a total pf 8–9 soft rays. The anal fin has a single spine and 8-9 soft rays. It closely resembles Eviota albolineata and its counts or measurements match closely. There are , however, distinct differences in colour, both in live and preserved specimens with this species having a dark spot on the underside of the head about in line with the rear part of the jaws and it also has a few scattered melanophores on the ventral side of the lower jaw near its tip, the intensity of the dark pigmentation varies, from just a few melanophores to a patch of very dark colour, this feature is absent in E. albolineata.

Colour varies from a partly transparent olive-green to a dark brown/green or a golden/yellow, with the lower surfaces generally paler. Scales have a darker edge giving a reticulated pattern, especially on the upper half. The caudal (tail), anal and dorsal fins are dusky with off-white to translucent spines and white to yellow rays; the caudal and anal fins may have a thin reddish or dark margin; pelvic fins are white and the pectoral fins are transparent often with a dark mark at the base of the fin. A. macleayi may be differentiated from other fish of the genus Ambassis by the relatively deep body, high gill raker count, interrupted lateral line and the dark spot at the base of the pectoral fins.

The largest species, called simply the nurse shark Ginglymostoma cirratum, may reach a length of ; the tawny nurse shark Nebrius ferrugineus is somewhat smaller at , and the short-tail nurse shark Pseudoginglymostoma brevicaudatum is by far the smallest at just in length. The first of the three species may reach a weight of 110 kg. Yellowish to dark brown in colour, nurse sharks have muscular pectoral fins, two spineless dorsal fins (the second of which is smaller) in line with the pelvic and anal fins, and a tail exceeding one quarter the shark's body length. The mouth of nurse sharks is most distinctive; it is far ahead of the eyes and before the snout (subterminal), an indication of the bottom-dwelling (benthic) nature of these sharks.

The front edges of the dorsal fins and the pectoral fins are hardened into stiff spines that can be locked into place. The body shape is cylindrical along its entire length. M. notata can be distinguished from other members of the genus Microsynodontis by examining the pectoral spine, the length of the caudal peduncle, the size of the eye, the shape of the caudal fin, and the colors on the body. The caudal peduncle is long, making up about 10% to 12% of the standard length of the fish, whereas all other members of the genus, with the exception of M. christyi and M. laevigatus, have a shorter caudal peduncle, making up about 6% to 10% of the standard length.

McCulloch The duskyshoulder trevally is one of the smallest fish in the genus Carangoides, reaching only 27 cm in length. The species is similar to other jacks in its overall body profile, having a compressed ovate to oblong shape, with the dorsal profile more convex than the ventral profile. The head profile is gently sloping and slightly convex, with large males having a distinct bulge that is absent in females and juveniles of both sexes. Both of the jaws contain anteriorly widening bands of small villiform teeth, with older individuals also having a number of larger outer teeth. Two separate dorsal fins occur, the first consisting of eight spines and the second of one spine and 20 to 22 soft rays.

The common torpedo (Torpedo torpedo), also known as ocellate torpedo or eyed electric ray, is a species of electric ray in the family Torpedinidae. It is found in the Mediterranean Sea and the eastern Atlantic Ocean from the Bay of Biscay to Angola, and is a benthic fish typically encountered over soft substrates in fairly shallow, coastal waters. Growing to long, this species has a nearly circular pectoral fin disc and a short, thick tail with two dorsal fins of nearly equal size and a large caudal fin. It can be identified by the prominent blue spots on its back, which usually number five but may vary from zero to nine, as well as by the small knobs on the rims of its spiracles.

Tetronarce californica also known as the Pacific electric ray is a species of electric ray in the family Torpedinidae, endemic to the coastal waters of the northeastern Pacific Ocean from Baja California to British Columbia. It generally inhabits sandy flats, rocky reefs, and kelp forests from the surface to a depth of , but has also been known to make forays into the open ocean. Measuring up to long, this species has smooth-rimmed spiracles (paired respiratory openings behind the eyes) and a dark gray, slate, or brown dorsal coloration, sometimes with dark spots. Its body form is typical of the genus, with a rounded pectoral fin disc wider than long and a thick tail bearing two dorsal fins of unequal size and a well-developed caudal fin.

A darker-pigmented individual The blue trevally is a moderately large fish, growing to a recorded maximum length of 70 cm and a weight of 8 kg. The species is similar in general morphology to a number of other trevallies in the genus Carangoides, having a compressed, oblong body, with the dorsal profile more convex than the ventral profile. Unlike most of the Carangoides, however, the blue trevally's snout is bluntly rounded, resembling the snouts of the pompanos of the genus Trachinotus and the lips of adults are notably fleshy. Two separate dorsal fins are found, the first having eight spines, while the second consists of one spine and 26 to 34 soft rays; more than any other species in Carangoides.

The common ling is the longest and one of the largest of the cod-like fish, the Gadiformes, which can reach lengths of 200 cm and weights of 30 kg. It is long and slender with a small head and small eyes and a large mouth, which has large teeth, with the upper jaw projecting beyond the lower jaw, which bears an obvious sensory barbel. Of the two dorsal fins, the anterior dorsal fin is short, having 14–15 fin rays, with a rounded profile, while the posterior dorsal fin is much longer with 61–68 fin rays and is uniform in height and is similar in length to the anal fin. The anal fin is also elongated and has 58-64 fin rays.

Stephan Swanson came to prominence as a marine researcher when he successfully placed the satellite transmitter on the famous Great white shark Nicole, the first great white shark ever to be tracked on a 20,000 kilometer migration from South Africa to Australia and back. Due to his ability to handle large marine predators, such as the great white shark, he was contracted as an expedition biologist to travel to Guadeloupe and place satellite transmitters on the dorsal fins of Great Whites. His historical capture and release of a 5m long, 1800 kilogram great white shark is documented in the National Geographic Marine Special "Ultimate Shark". Swanson is currently co-owner of False Bay White Shark Adventures (trading as Shark Explorers) which was established in 2008.

Highfin sperm whale The high- finned sperm whale, or the high-finned cachalot, is an alleged variant or relative of the known sperm whale, Physeter macrocephalus, with an unusually tall dorsal fin from the North Atlantic. The physician Sir Robert Sibbald, in 1687, described an alleged stranded female individual on Orkney, saying its dorsal fins was similar to a "mizzen mast", and the whale, based on Sibbald's account, was described as P. tursio. However, naturalist Georges Cuvier disregarded Sibbald's claim as a bad description of the carcass, as well as dismissing the name P. tursio. Another alleged sighting was off the Annapolis Basin, Nova Scotia, Canada on September 27, 1946, where the creature was apparently trapped there for two days.

It has a slender, streamlined body and can be identified by its short round snout, long sickle-shaped pectoral fins, ridge between the first and second dorsal fins, and faintly marked fins. Adult dusky sharks have a broad and varied diet, consisting mostly of bony fishes, sharks and rays, and cephalopods, but also occasionally crustaceans, sea stars, bryozoans, sea turtles, marine mammals, carrion, and garbage. This species is viviparous with a three-year reproductive cycle; females bear litters of 3-14 young after a gestation period of 22-24 months, after which there is a year of rest before they become pregnant again. Females are capable of storing sperm for long periods, as their encounters with suitable mates may be few and far between due to their nomadic lifestyle and low overall abundance.

Dense innervation of arteries in seals by sympathetic nerves may be part of a system for maintaining vasoconstriction of the dive response independent of local metabolite induced vasodilation. Venous capacitance is highly developed, especially in phocid seals and whales, and includes a large hepatic sinus and posterior vena cava, and is thought to be related to the large blood volume of the animals. The relatively large spleen also injects extremely high hematocrit blood into the hepatic sinus during dives, and is a significant storage organ for red blood cells. Parallel counter-flowing arteries and veins characteristic of countercurrent exchange units are present in the dorsal fins, flukes, and flippers of cetaceans, and are considered to conserve body heat by transferring it to the returning venous flow before arterial blood is exposed to the high heat-loss areas.

This species is widely distributed and is frequently seen by divers in Indonesian waters with their heads and anterior bodies protruding from crevices in sand and rubble habitats from very shallow to about 60 m. Although generally placed in the moray eel family Muraenidae, it has several distinctive features leading some to place it in its own family, Rhinomuraenidae.... The ribbon eel is a creature bearing a resemblance to a mythical Chinese dragon with a long, thin body and high dorsal fins. The ribbon eel can easily be recognised by its expanded anterior nostrils. They are well known for their characteristic jaws that are frequently opened very widely when a diver approaches Based on observed colour changes, it is generally considered a protandric hermaphrodite (first male, then changing sex to female), although this has yet to be confirmed.

His local MP, Vernon Shearer, telephoned Malan and together with Smith persuaded him to send the South African Air Force to fetch the fish and bring it back to South Africa. Because the second specimen differed from the first one in two key ways, it lacked the first dorsal fin and its tail fin was truncated, Smith named the fish in honour of Malan and the place where the fish was caught, Malania anjouanae.Weinberg, Samantha, A Fish Caught in Time: the Search for the Coelacanth, New York: HarperCollins Publishers, 2006, pp. 63–82. Eventually, it was established that this was not a different species at all, and exactly the same fish as the first specimen, Latimeria chalumnae; the apparent differences were down to a shark attack that cost the fish one of its dorsal fins and part of its tail.

The chub mackerel has a well-developed swim bladder attached with the esophagus, which the "true mackerels" in the genus Scomber lack, and a characteristic color difference is seen between the chub and the Atlantic chub, the latter being silvery-sided below the midline, whereas the lower part of the sides of the chub (otherwise colored somewhat like the Atlantic) are mottled with small dusky blotches, and the chub has a larger eye than the Atlantic. Less obvious differences are that the dorsal fins are closer together in the chub and only 9 or 10 spines are in its first dorsal fin instead of 11 or more, which is the usual count in the Atlantic mackerel. In most species, the mackerel is known to travel in large schools. It is a smaller fish than its better-known relatives, growing to a length around .

In his famous 1824 paper that described the almost complete plesiosaur skeleton discovered by Anning in 1823 Conybeare mentioned examining a plesiosaur skull in the possession of "Miss Philpot". In 1834 Buckland arranged for the Swiss palaeontologist Louis Agassiz to visit Lyme to work with Elizabeth Philpot and Anning to obtain and study fish fossils found in the region. They were able to show him fossils of 34 different species, and he was so impressed by the knowledge of Philpot and Anning that he wrote in his journal: "Miss Philpot and Mary Anning have been able to show me with utter certainty which are the ichthyodorulites dorsal fins of sharks that correspond to different types." He thanked both women for their help in his monumental book, Studies of Fossil Fish, and he named a fossil fish species, Eugnathus philpotae, after Philpot and another two species after Anning.

Macroudidae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a single barbel on the chin, projecting snouts, and slender bodies that taper to whip-like tails, without an obvious caudal fin but what there is of the caudal fin is often confluent with the posterior dorsal and anal fins. There are normally two dorsal fins, the anterior dorsal fin is quite high, the posterior quite low but is longer and takes up a greater proportion of the fish's of the back, species in the subfamily Macrouroidinae have a single dorsal fin. The long anal fin is almost as long as the second dorsal fin is nearly as long as the posterior dorsal, and sometimes it is longer.

Chelidonichthys kumu (Cuvier, 1829)The red gurnard is a bottom-dwelling fish known for its bright red body and large, colorful pectoral fins with a large black eye-spot in the center and surrounded by a bright blue edge (Eichelsheim, 2010; Rainer & Reyes, 2019). Its natural color is a splotchy pale brown, generally only becoming red when stressed and the belly is paler or even white (Lang, 2000). It has a boxy, bony head which is protected by backwards-facing spines along the front of the snout and around the eye as well as on the hind margin of the operculum (Ayling & Cox, 1982) and tapers into a laterally elongated body with 33-35 vertebrae. There are 8-10 gill rakers and 70-80 scales on its lateral line, which is uninterrupted. Its two tall, triangular dorsal fins have a total of 15-16 soft rays and 9-10 spines.

This acts as a counter-current exchange system which short-circuits the warmth from the arterial blood directly into the venous blood returning into the trunk, causing minimal heat loss from the extremities in cold weather. The subcutaneous limb veins are tightly constricted, thereby reducing heat loss via this route, and forcing the blood returning from the extremities into the counter-current blood flow systems in the centers of the limbs. Birds and mammals that regularly immerse their limbs in cold or icy water have particularly well developed counter- current blood flow systems to their limbs, allowing prolonged exposure of the extremities to the cold without significant loss of body heat, even when the limbs are as thin as the lower legs, or tarsi, of a bird, for instance. When animals like the leatherback turtle and dolphins are in colder water to which they are not acclimatized, they use this CCHE mechanism to prevent heat loss from their flippers, tail flukes, and dorsal fins.

Retrieved 21 May 2013. Modifications made to the HTTB included extended chord ailerons, a long chord rudder, fast-acting double-slotted trailing edge flaps, a high-camber wing leading edge extension, a larger dorsal fin and dorsal fins, the addition of three spoiler panels to each wing upper surface, a long-stroke main and nose landing gear system, and changes to the flight controls and a change from direct mechanical linkages assisted by hydraulic boost, to fully powered controls, in which the mechanical linkages from the flight station controls operated only the hydraulic control valves of the appropriate boost unit.The High Technology Test Bed Lockheed Service News Vol. 12 No. 3, September 1985. Retrieved 21 May 2013. The HTTB first flew on 19 June 1984, with civil registration of N130X. After demonstrating many new technologies, some of which were applied to the C-130J, the HTTB was lost in a fatal accident on 3 February 1993, at Dobbins Air Reserve Base, in Marietta, Georgia.

A grayling In the United Kingdom, in the early autumn, fishermen often use the name of the grayling (Thymallus thymallus) as a by-word for their seasonal jolly: a Grayling Day is often fisherman-talk for a party. Many clubs as well as fisherman friends will organise their annual Grayling Day in the autumn when it is traditional for there to be large quantities of both food and drink, prefaced by a token amount of fishing.Grayling Day "Fishing magic" Retrieved 13/1/2011 Gayling day "Flyforums" Retrieved 13/1/2011 At the event, there will often be speeches and toasts. The celebration is named after the grayling due to its popularity with fishermen: apart from having one of the most beautiful dorsal fins of any fish, the grayling rises freely to the surface and reaches its peak when the temperature starts to fall, making an easy catch for fishermen in the middle of the trout closed season.

Scientists from the National Marine Fisheries Service (NMFS) have reported that "the collapsed dorsal fins commonly seen in captive killer whales do not result from a pathogenic condition, but are instead thought to most likely originate from an irreversible structural change in the fin's collagen over time. Possible explanations for this include: (1) alterations in water balance caused by the stresses of captivity dietary changes, (2) lowered blood pressure due to reduced activity patterns, or (3) overheating of the collagen brought on by greater exposure of the fin to the ambient air." According to SeaWorld's website, another reason for the fin to bend may be the greater amount of time that captive whales spend at the surface, where the fin is not supported by water pressure. The Whale and Dolphin Conservation says that dorsal fin collapse is largely explained by captive killer whales swimming in small circles due to the inadequate space in which they have to swim.

They therefore argue that Spinosaurus used its dorsal neural sail in the same manner as sailfish, and that it also employed its long narrow tail to stun prey like a modern thresher shark. Sailfish employ their dorsal fins for herding schools of fish into a "bait ball" where they cooperate to trap the fish into a certain area where the sailfish can snatch the fish with their bills. The sail could have possibly reduced yaw rotation by counteracting the lateral force in the direction opposite to the slash as suggested by Gimsa and colleagues (2015). Gimsa and colleagues specifically wrote : Side view of reconstructed skeleton Spinosaurus anatomy exhibits another feature that may have a modern analogy: its long tail resembled that of the thresher shark, employed to slap the water to herd and stun shoals of fish before devouring them (Oliver and colleagues, 2013). The strategies that sailfish and thresher sharks employ against shoaling fish are more effective when the shoal is first concentrated into a ‘bait ball’ (Helfman, Collette & Facey, 1997; Oliver and colleagues, 2013; Domenici and colleagues, 2014).