A fish is an aquatic, anamniotic, gill-bearing vertebrate with a tough cranium to protect the brain. Many fish have fins that they use for directional stability and propulsion. Fish can be grouped into the more basaljawless fish and the more common jawed fish, the latter including all livingcartilaginous and bony fish, as well as the extinct placoderms and acanthodians. Tetrapods are descended from fish, so in a break from the long tradition of grouping all fish into a single class (Pisces), modern phylogenetics views fish as a paraphyletic group that includes all vertebrates except tetrapods. To treat fish as a monophyletic group, one would have to classify tetrapods as a clade/subgroup of specialized fish, which would make "fish" and "vertebrates" synonyms. In English, the plural of "fish" is fish when referring to individuals and fishes when referring to species.
Ornithoprion had a unique projection of its lower jaw termed the mandibular rostrum, which was covered by a beak of fused bony scales whose function is unknown. It inhabited shallow, seasonal marine and brackish water environments, alongside a variety of other cartilaginous fishes. The rounded shape of Ornithoprion's teeth suggests that it hunted hard-shelled invertebrates, and bite marks and damage to some of its fossils indicate that it was in turn fed on by other carnivores. Ornithoprion was small relative to other members of its order, with a cranium length of up to 10cm (3.9in) and an estimated body length of up to approximately 91cm (36in). (Full article...)
Clownfish or anemonefishes (genus Amphiprion) are saltwater fish found in the warm and tropical waters of the Indo-Pacific. They mainly inhabit coral reefs and have a distinctive colouration typically consisting of white vertical bars on a red, orange, yellow, brown or black background. Clownfish developed a symbiotic and mutually beneficial relationship with sea anemones, on which they rely for shelter and protection from predators. In turn, clownfish protect the anemone from anemone-eating fish, as well as clean and fan them, and attract beneficial microorganisms with their waste.
Clownfish are omnivorous and mostly feed on plankton. They live in groups consisting of a breeding female and male, along with some non-breeding individuals. Clownfish have a size-based dominance hierarchy with the breeding female ranking at the top, followed by the breeding male and then the largest non-breeder and so on. When the female disappears, the breeding male changes sex and takes her place while the others move up the hierarchy. During reproduction, the female deposits eggs on a rock near their anemone, and the male fertilises them. After hatching, clownfish disperse into the open ocean as larvae, eventually settling on the bottom and searching for an anemone host as juveniles. (Full article...)
Named for its pale coloration, it is closely related to the more common shovelnose sturgeon (Scaphirhynchus platorynchus), but is much larger, averaging between 30 and 60 inches (76 and 152cm) in length and 85 pounds (39kg) in weight at maturity. This species takes 15years to mature and spawns infrequently, but can live up to a century. A member of the sturgeon family, Acipenseridae, which originated during the Cretaceous period 70million years ago, the pallid sturgeon has changed little since then. (Full article...)
Thinopus is the name given to a trace fossil (ichnotaxon) found in late Devonian rocks in Pennsylvania. The only specimen was described by paleontologistOthniel Charles Marsh in a brief note published in 1896, with the only ichnospeciesThinopus antiquus. Marsh interpreted it as the fossil footprints of an early amphibian, making it the oldest evidence for tetrapods (land vertebrates) known at the time. Later research, however, argued that the fossil is better interpreted as the impressions of coprolites (fossilized feces) of fish. This would make Thinopus the earliest published name of a fish coprolite. (Full article...)
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The estuary stingray (Hemitrygon fluviorum), also called the estuary stingaree or brown stingray, is a species of stingray in the familyDasyatidae. Endemic to eastern Australia, it typically inhabits shallow, mangrove-lined tidal rivers, estuaries, and bays in southern Queensland and New South Wales. This yellow-brown to olive ray grows to at least 93cm (37in) across. It has a diamond-shaped pectoral fin disc and a mostly smooth, whip-like tail bearing both dorsal and ventral fin folds. It can additionally be identified by its long, narrow nostrils and the row of thorns along the midline of its back.
The marbled electric ray (Torpedo marmorata) is a species of electric ray in the familyTorpedinidae found in the coastal waters of the eastern Atlantic Ocean from the North Sea to South Africa. This benthic fish inhabits rocky reefs, seagrass beds, and sandy and muddy flats in shallow to moderately deep waters. It can survive in environments with very little dissolved oxygen, such as tidal pools. 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 36–38cm (14–15in) and 55–61cm (22–24in) long respectively.
Nocturnal and solitary, the marbled electric ray can often be found lying the sea floor buried except for its eyes and spiracles. This slow-moving predator feeds almost exclusively on small bony fishes, which it ambushes from the bottom and subdues with strong electric bursts. It defends itself by turning towards the threat, swimming in a loop, or curling up with its underside facing outward, while emitting electric shocks to drive off the prospective predator. Its paired electric organs are capable of producing 70–80 volts of electricity. This species is aplacental viviparous, with the developing embryos sustained by yolk and histotroph ("uterine milk") produced by the mother. Mating takes place from November to January, and females bear litters of 3–32 pups every other year after a gestation period of 9–12 months. The newborn ray is immediately capable of using electricity to hunt. (Full article...)
The blacktip reef shark (Carcharhinus melanopterus) is a species of requiem shark, in the family Carcharhinidae, which can be easily identified by the prominent black tips on its fins (especially on the first dorsal fin and its caudal fin). Among the most abundant sharks inhabiting the tropicalcoral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters. Its exposed first dorsal fin is a common sight in the region. The blacktip reef shark is usually found over reef ledges and sandy flats, though it has also been known to enter brackish and freshwater environments. It typically attains a length of 1.6m (5.2ft). Like other sharks, the females are larger than the males.
The blacktip reef shark has extremely small home ranges and exhibits strong site fidelity, remaining within the same local area for up to several years at a time. It is an active predator of small bony fish, cephalopods, and crustaceans, and has also been known to feed on sea snakes and seabirds. Accounts of the blacktip reef shark's life history have been variable and sometimes contradictory, in part reflecting geographical differences within the species. Like other members of its family, this shark is viviparous, with females giving birth to two to five young on a biennial, annual, or possibly biannual cycle. Reports of the gestation period range from 7–9, through 10–11, to possibly 16 months. Mating is preceded by the male following closely behind the female, likely attracted by her chemical signals. Newborn sharks are found further inshore and in shallower water than adults, frequently roaming in large groups over areas flooded by high tide. (Full article...)
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Toxotes chatareus, sometimes known by the common namescommon archerfish, seven-spot archerfish or largescale archerfish, is a species of perciform fish in the archerfish genus Toxotes.
They are usually no larger than 20 centimetres (7.9in) but may grow up to 40 centimetres (16in). Unlike most archerfish, T.chatareus are sooty rather than silvery in colour. They are omnivorous, feeding on insects, fish, and vegetative matter at the surface of the water. Breeding occurs in the wet season, and 20,000 to 150,000 eggs may be laid at one time. (Full article...)
The whale shark (Rhincodon typus) is a slow-moving, filter-feedingcarpet shark and the largest known extantfishspecies. An individual with a length of 18.8m (61.7ft) has been considered the largest reliably recorded. The whale shark holds many records for size in the animal kingdom, most notably being by far the largest living non-cetacean animal. It is the only living species of the genus Rhincodon and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984, it was classified as Rhiniodon into Rhinodontidae. An extinct species, Rhincodon ferriolensis, was described in Europe (probably in Spain), in the Late Burdigalian stage.
The whale shark is an active filter feeder, primarily consuming plankton, krill, fish eggs, and small schooling fish such as sardines and anchovies. The shark can process over 6,000 liters of water per hour through its specialized sieve-like gill pads. Highly migratory, the whale shark travels thousands of miles across tropical oceans to exploit seasonal food sources, with large, predictable feeding aggregations occurring at coastal sites such as Ningaloo Reef in Western Australia, the Yucatan Peninsula in Mexico, and off the coast of Gujarat and Kerala in India. Despite its immense size, the whale shark is docile and poses no significant threat to humans. It is currently listed as an Endangered species on the IUCN Red List owing to a population decline of more than 50% over the last 75 years, primarily as a result of targeted fishing, bycatch in other fisheries, and collisions with large ships. (Full article...)
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The Australian weasel shark (Hemigaleus australiensis) is an uncommon species of ground shark in the familyHemigaleidae. It inhabits shallow waters off northern Australia to a depth of 170m (560ft); smaller sharks frequent sand and seagrasshabitat and shift to coral reefs as they grow older. A slim, drab species reaching a length of 1.1m (3.6ft), it has sickle-shaped fins with dark tips on the second dorsal fin and caudal fin upper lobe. Its upper teeth are broad with strong serrations only on the trailing edge. The lateral line along each side is prominent and exhibits a downward curve below the second dorsal fin.
The bluespotted ribbontail ray (Taeniura lymma) is a species of stingray in the family Dasyatidae. Found from the intertidal zone to a depth of 30m (100ft), this species is common throughout the tropical Indian and western Pacific Oceans in nearshore, coral reef–associated habitats. It is a fairly small ray, not exceeding 35cm (14in) in width, with a mostly smooth, oval pectoral fin disc, large protruding eyes, and a relatively short and thick tail with a deep fin fold underneath. It can be easily identified by its striking color pattern of many electric blue spots on a yellowish background, with a pair of blue stripes on the tail.
At night, small groups of bluespotted ribbontail rays follow the rising tide onto sandy flats to root for small benthic invertebrates and bony fishes in the sediment. When the tide recedes, the rays separate and withdraw to shelters on the reef. Reproduction is through Ovoviviparity, with females giving birth to litters of up to seven young. This ray is capable of injuring humans with its venomous tail spines, though it prefers to flee if threatened. Because of its beauty and size, the bluespotted ribbontail ray is popular with private aquarists despite being poorly suited to captivity. (Full article...)
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The sicklefin weasel shark (Hemigaleus microstoma) is an uncommon species of ground shark in the familyHemigaleidae. It is native to southern India, southern China, and parts of Southeast Asia, living in shallow waters down to a depth of 170m (560ft). 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 1.1m (3.6ft).
Spending most of its time close to the sea floor, the sicklefin weasel shark is a specialist predator of cephalopods. Its reproductive mode is viviparous, in which the unborn young form a placental connection to their mother. Females probably give birth twice a year, with each litter consisting of two to four pups. The sicklefin weasel shark is widely caught by artisanal fisheries and used for meat, fins, and fishmeal; its low natural abundance and reproductive rate mean that it cannot sustain much fishing pressure. Given that fishing activity is intense throughout its range, the International Union for Conservation of Nature (IUCN) has assessed this species as vulnerable. (Full article...)
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The smooth hammerhead (Sphyrna zygaena) is a species of hammerhead shark, and part of the family Sphyrnidae. This species is named "smooth hammerhead" because of the distinctive shape of the head, which is flattened and laterally extended into a hammer shape (called the "cephalofoil"), without an indentation in the middle of the front margin (hence "smooth"). Unlike other hammerheads, this species prefers temperate waters and occurs worldwide at medium latitudes. In the summer, these sharks migrate towards the poles following cool water masses, sometimes forming schools numbering in the hundreds to thousands.
The second-largest hammerhead shark after the great hammerhead shark, the smooth hammerhead can measure up to 5m (16ft) long. It is an active predator that takes a wide variety of bony fishes and invertebrates, with larger individuals also feeding on sharks and rays. As in the rest of its family, this shark is viviparous and gives birth to litters of 20–40 pups. A relatively common shark, it is captured, intentionally or otherwise, by many commercial fisheries throughout its range; its fins are extremely valuable for use in shark fin soup. This shark is potentially dangerous and has likely been responsible for a few attacks on humans, though it is less likely to encounter swimmers than other large hammerhead species due to its temperate habitat. (Full article...)
Female yellow stingrays are larger than males. Females reach about a maximum length of about 26 inches whereas the male will reach a maximum length of about 15 inches across. The yellow stingray has a round pectoral fin disc and a short tail with a well-developed caudal fin. It has a highly variable but distinctive dorsal color pattern consisting of either light-on-dark or dark-on-light reticulations forming spots and blotches, and can rapidly change the tonality of this coloration to improve its camouflage. (Full article...)
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The finetooth shark (Carcharhinus isodon) is a species of requiem shark, in the family Carcharhinidae, found in the western Atlantic Ocean, from North Carolina to Brazil. It forms large schools in shallow, coastal waters, and migrates seasonally following warm water. A relatively small, slender-bodied shark, the finetooth shark can be identified by its needle-like teeth, dark blue-gray dorsal coloration, and long gill slits. It attains a maximum length of 1.9m (6.2ft). The diet of this species consists primarily of small bony fishes, in particular menhaden. Like other members of its family, it is viviparous with females giving birth to two to six pups in estuarine nursery areas every other year.
Valued for its meat, the finetooth shark forms an important component of the commercialgillnet shark fishery operating off the southeastern United States. Population assessments suggest that this fishery does not currently pose a threat to U.S. populations of the species. This shark is not known to pose a danger to humans, though it snaps vigorously when captured and should be handled with caution. (Full article...)
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 localized 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. This shark typically reaches lengths of 1.9–2.5m (6.2–8.2ft).
The pigeye shark is an apex predator that mostly hunts low in the water column. It has a varied diet, consisting mainly of bony and cartilaginous fishes and also including crustaceans, molluscs, sea snakes, and cetaceans. This species gives birth to live young, with the developing embryos sustained to term via a placental connection to their mother. Litters of three to thirteen pups are born after a gestation period of nine or twelve months. Young sharks spend their first few years of life in sheltered inshore habitats such as bays, where their movements follow tidal and seasonal patterns. The pigeye shark's size and dentition make it potentially dangerous, though it has not been known to attack humans. The shark is infrequently caught in shark nets protecting beaches and by fisheries, which use it for meat and fins. The IUCN presently assesses this species as vulnerable. (Full article...)
Image 3Shortfin mako shark make long seasonal migrations. They appear to follow temperature gradients, and have been recorded travelling more than 4,500 km in one year. (from Pelagic fish)
Image 10Coral reefs support flourishing ecosystems, paradoxically in clear, low nutrient waters, along tropical continental coasts and around volcanic islands. Coral reef fish are numerous and diverse. (from Coastal fish)
Image 22Oceanic fish inhabit the oceanic zone, which is the deep open water which lies beyond the continental shelves. (from Pelagic fish)
Image 23The stargazer is an ambush predator which can deliver both venom and electric shocks. It has been called "the meanest thing in creation". (from Coastal fish)
Image 30Most mesopelagic fishes are small filter feeders that ascend at night to feed in the nutrient rich waters of the epipelagic zone. During the day, they return to the dark, cold, oxygen-deficient waters of the mesopelagic where they are relatively safe from predators. Lanternfish account for as much as 65% of all deep sea fish biomass and are largely responsible for the deep scattering layer of the world's oceans. (from Pelagic fish)
Image 32Young, red flabby whalefish make nightly vertical migrations into the lower mesopelagic zone to feed on copepods. When males mature into adults, they develop a massive liver and then their jaws fuse shut. They no longer eat, but continue to metabolise the energy stored in their liver. (from Pelagic fish)
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The global continental shelf, highlighted in light blue
Image 34Surgeonfish are among the most common of coral reef herbivores, often feeding in shoals. This may be a mechanism for overwhelming the highly aggressive defence responses of small territorial damselfishes that vigorously guard small patches of algae on coral reefs. (from Coral reef fish)
Image 35The rattail Coryphaenoides armatus (abyssal grenadier) on the Davidson Seamount at a depth of 2,253 metres (7,392ft). (from Deep-sea fish)
Image 36Long-snouted lancetfish. Lancetfish are ambush predators which spend all their time in the mesopelagic zone. They are among the largest mesopelagic fishes (up to 2m (6.6ft). (from Deep-sea fish)
Image 44Areas of upwelling in red (from Pelagic fish)
Image 45Many bristlemouth species, such as the "spark anglemouth" above, are also bathypelagic ambush predators that can swallow prey larger than themselves. They are among the most abundant of all vertebrate families. (from Pelagic fish)
Image 46Most of the rest of the mesopelagic fishes are ambush predators, such as this sabertooth fish. The sabertooth uses its telescopic, upward-pointing eyes to pick out prey silhouetted against the gloom above. Their recurved teeth prevent a captured fish from backing out. (from Pelagic fish)
Image 48In the foreground is an orange-lined triggerfish displaying spines. Triggerfish have mouths that crush shells. Orange-lined triggerfish are particularly aggressive. The black and white fish are three-stripe damselfish and the unstriped fish are blue-green chromis damselfish. If the triggerfish attacks, the damselfish will hide in the nearby cauliflower coral. If the triggerfish wants to hide, it will squeeze into a coral crevice and lock itself in place with its spines. (from Coral reef fish)
Image 49The giant whale shark, another resident of the ocean epipelagic zone, filter feeds on plankton, and periodically dives deep into the mesopelagic zone. (from Pelagic fish)
Image 50Lanternfish are partial residents of the ocean epipelagic zone During the day they hide in deep waters, but at night they migrate up to surface waters to feed. (from Pelagic fish)
The spotted trunkfish (Lactophrys bicaudalis) is a species of ray-finned fish in the family Ostraciidae, native to the Caribbean Sea and parts of the western Atlantic Ocean. Members of this family are known as boxfishes because they have a hard outer covering consisting of hexagonal, plate-like scales fused together into a solid, triangular or box-like carapace. Because of this casing, the body of the spotted trunkfish is not flexible, and locomotion is normally limited to slow movements performed by rippling its dorsal and anal fins and gently beating its pectoral fins. If faster motion is required, it can additionally use its caudal fin for propulsion. This spotted trunkfish was photographed at a depth of about 40ft (12m) at Bari Reef, Bonaire.
An Atlantic salmon (Salmo salar) egg hatching. The Alevin (larva) has grown around the remains of the yolk sac - visible are the arteries spinning around the yolk and little oildrops, also the gut, the spine, the main caudalblood vessel, the bladder and the arcs of the gills. In about 24 hours it will be a fry without yolk sac.
Rhinogobius flumineus, also known as the lizard goby, is a species of goby in the family Oxudercidaeendemic to Japan, seen here in Hamamatsu, Shizuoka Prefecture. A small freshwater fish found in fast-flowing streams, it maintains its position against the current by gripping a rock with a sucker formed from two of its fins. The fish's mouth is slightly asymmetric; dextral (right-sided) fish tend to curve their bodies to the right as they rest, while sinistral (left-sided) fish tend to adopt a left-curving posture. The fish are omnivorous, picking edible items off the stream bed with the side of the mouth, but dextral and sinistral fish show no preference for which side of the mouth they use for this purpose.
A sketch of a longnose sawshark (Pristiophorus cirratus), a species of sawshark found in the eastern Indian Ocean around southern Australia on the continental shelf at depths of between 40 and 310m (130 and 1,020ft). It is a medium-sized shark with a saw-like flattened snout which measures up to thirty percent of its body size.
The flying gurnard is a fish of tropical to warm temperate waters on both sides of the Atlantic Ocean. When excited, it spreads its "wings", semi-transparent appendages tipped with a phosphorescent bright blue coloration which are used to frighten predators.
Koi are ornamental domesticated varieties of the common carpCyprinus carpio, originated from China and widely spread in Japan. They are very closely related to goldfish. The word "koi" comes from Japanese meaning "carp".
In American English, the name gar (or garpike) is strictly applied to members of the Lepisosteidae, a family including seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine, waters of eastern North America, Central America, and the Caribbean islands.
The leopard shark (Triakis semifasciata) is a species of hound shark found along the Pacific coast of North America from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5 m (3.9–4.9 ft) long, this slender-bodied shark is characterized by black saddle-like markings and large spots over its back.
The orbicular batfish (Platax orbicularis) is a batfish endemic to the Indian and Pacific Oceans. It has a thin, disc-shaped body, and male can grow up to 50 centimetres (20in) in length. In the wild, the orbicular batfish lives in brackish or marine waters, usually around reefs, at depths from 5 to 30 metres (20 to 100ft). It is also a popular aquarium fish, although captive specimens generally do not grow as long as wild ones.
A discus (Symphysodon discus) is guarding its eggs. As for most cichlids, brood care is highly developed with both the parents caring for the young. Additionally, adult discus produce a secretion through their skin, off which the larvae live during their first few days.
People jigging—fishing with a type of lure known as a "jig"—for squid in Queenscliff, Victoria, Australia. A jig consists of a lead sinker with a hook molded into it and usually covered by a soft body to attract fish. Jigs are intended to create a jerky, vertical motion, as opposed to spinnerbaits which move through the water horizontally.
Brachysomophis cirrocheilos, the stargazer snake eel, is a marine fish belonging to the family Ophichthidae. It is native to shallow tropical and subtropical waters in the western Indo-Pacific region. It hunts at night for crustaceans and small fish, after which it submerges itself into the sediment tail first and remains there all day, with just its eyes and the top of its head projecting, as seen here in Batangas Bay in the Philippines.
The Siamese fighting fish (Betta splendens), or fighting betta is a freshwaterfish related to the paradise fish. The fighting fish is a species in the Gourami family which is popular as an aquarium fish. They are called pla-kad (biting fish) in Thai or trey krem in Khmer. They are a very territorial fish and it is unwise to house two males together. Even the females may become territorial towards each other if not housed in a large enough tank.
The Oscar (Astronotus ocellatus) is a species of fish from the cichlidfamily. In South America, where the species occurs, they are often found for sale as a food fish in the local markets. The species is also a popular aquarium fish. They have been reported to grow to a length of 45cm (ca. 18in) and a mass of 1.6kg (3.5lb).
The Atlantic spadefish is a species of marine fish endemic to the shallow waters off the coast of the southeastern United States and in the Caribbean Sea. They are similar in appearance to fresh waterangelfish, but much larger, reaching up to three feet (0.9 m) in length. Due to their reputation as strong fighters, they are popular game fish, especially during the summer months when they are most active.
The Mini Edition of the Fish Portal is available for you to use on your wikipedia user page or talk page. It uses minimum space but retains many crucial features of the portal. To use it, place {{Portal:Fish/Mini portal}} on the designated page. See here for an example of the mini portal on a user page.
The Fish Quiz is a friendly quiz competition designed to test your general knowledge of fish. The current game is Fish Quiz Tournament X. You can read more and join the game here.
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