Portal:Fish

The Fish Portal

Ocellaris clownfish (Amphiprion ocellaris) in Papua New Guinea

A fish is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a tough cranium to protect the brain, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. 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. In English, the plural of "fish" is fish when referring to individuals and fishes when referring to species.

The earliest fish appeared during the Cambrian as small filter feeders; they continued to evolve through the Paleozoic, diversifying into many forms. The earliest fish with dedicated respiratory gills and paired fins, the ostracoderms, had heavy bony plates that served as protective exoskeletons against invertebrate predators. The first fish with jaws, the placoderms, appeared in the Silurian and greatly diversified during the Devonian, the "Age of Fishes".

Bony fish, distinguished by the presence of swim bladders and later ossified endoskeletons, emerged as the dominant group of fish after the end-Devonian extinction wiped out the apex predators, the placoderms. Bony fish are further divided into lobe-finned and ray-finned fishes. About 96% of all living fish species today are teleosts- a crown group of ray-finned fish that can protrude their jaws. The tetrapods, a mostly terrestrial clade of vertebrates that have dominated the top trophic levels in both aquatic and terrestrial ecosystems since the Late Paleozoic, evolved from lobe-finned fish during the Carboniferous, developing air-breathing lungs homologous to swim bladders. (Full article...)

Selected article –

  • Image 1 A leopard shark and two blacksmith damselfish in Birch Aquarium The leopard shark (Triakis semifasciata) is a species of houndshark, in the family Triakidae. It is 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 immediately identifiable by the striking pattern of black saddle-like markings and large spots over its back, from which it derives its common name. Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock-strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4 m (13 ft) deep. Active-swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs. Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is aplacental viviparous, meaning that the young hatch inside the uterus and are nourished by yolk. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. It is relatively slow-growing and takes many years to mature. (Full article...)

    A leopard shark and two blacksmith damselfish in Birch Aquarium

    The leopard shark (Triakis semifasciata) is a species of houndshark, in the family Triakidae. It is 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 immediately identifiable by the striking pattern of black saddle-like markings and large spots over its back, from which it derives its common name. Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock-strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4 m (13 ft) deep.

    Active-swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs. Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is aplacental viviparous, meaning that the young hatch inside the uterus and are nourished by yolk. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. It is relatively slow-growing and takes many years to mature. (Full article...)
  • Image 2 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 5 m (16 ft) 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...)

    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 5 m (16 ft) 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...)
  • Image 3 Sand whiting taken near Byron Bay, New South Wales The sand whiting (Sillago ciliata), also known as the summer whiting, yellowfin whiting or blue-nose whiting, is a common species of coastal marine fish of the family Sillaginidae, the smelt-whitings. It is a slender, slightly compressed fish that is very similar to other species of Sillago, with detailed spine, ray and lateral line scale counts needed to distinguish the species between its nearest relative Sillago analis. The sand whiting is distributed along the east coast of Australia from Cape York south to Tasmania, as well as Lord Howe Island and New Caledonia in the Pacific Ocean. The sand whiting commonly inhabits shallow sandy substrates in bays, estuaries and surf zones where it preys on polychaete worms, small crustaceans and bivalve molluscs. Reproduction in the species is variable over its range, generally spawning twice between September and April. Young fish inhabit shallow sand flats, both along the coast and well into the upper reaches of estuaries. (Full article...)

    Sand whiting taken near Byron Bay, New South Wales

    The sand whiting (Sillago ciliata), also known as the summer whiting, yellowfin whiting or blue-nose whiting, is a common species of coastal marine fish of the family Sillaginidae, the smelt-whitings. It is a slender, slightly compressed fish that is very similar to other species of Sillago, with detailed spine, ray and lateral line scale counts needed to distinguish the species between its nearest relative Sillago analis. The sand whiting is distributed along the east coast of Australia from Cape York south to Tasmania, as well as Lord Howe Island and New Caledonia in the Pacific Ocean.

    The sand whiting commonly inhabits shallow sandy substrates in bays, estuaries and surf zones where it preys on polychaete worms, small crustaceans and bivalve molluscs. Reproduction in the species is variable over its range, generally spawning twice between September and April. Young fish inhabit shallow sand flats, both along the coast and well into the upper reaches of estuaries. (Full article...)
  • Image 4 The round ribbontail ray or blotched fantail ray, (Taeniurops meyeni) is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m (66–197 ft). Reaching 1.8 m (5.9 ft) across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail. Generally nocturnal, the round ribbontail ray can be solitary or gregarious, and is an active predator of small, benthic molluscs, crustaceans, and bony fishes. It is aplacental viviparous, with the embryos sustained by yolk, and later histotroph ("uterine milk") secreted by the mother; up to seven pups are born at a time. Although not aggressive, if provoked the round ribbontail ray will defend itself with its venomous tail spine, and it has been responsible for at least one fatality. It is valued by ecotourist divers and recreational anglers. This slow-reproducing species is threatened by commercial fishing, both targeted and bycatch, and habitat degradation across much of its range. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Vulnerable. (Full article...)

    The round ribbontail ray or blotched fantail ray, (Taeniurops meyeni) is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m (66–197 ft). Reaching 1.8 m (5.9 ft) across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail.

    Generally nocturnal, the round ribbontail ray can be solitary or gregarious, and is an active predator of small, benthic molluscs, crustaceans, and bony fishes. It is aplacental viviparous, with the embryos sustained by yolk, and later histotroph ("uterine milk") secreted by the mother; up to seven pups are born at a time. Although not aggressive, if provoked the round ribbontail ray will defend itself with its venomous tail spine, and it has been responsible for at least one fatality. It is valued by ecotourist divers and recreational anglers. This slow-reproducing species is threatened by commercial fishing, both targeted and bycatch, and habitat degradation across much of its range. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Vulnerable. (Full article...)
  • Image 5 A freshwater male Poecilia vandepolli, or Van de Poll's molly, is a poeciliid fish native to the Caribbean islands of Aruba, Bonaire, and Curaçao. It is one of the most common fish in its range, inhabiting fresh, brackish, salt, and hypersaline waters such as streams, ponds, bays, salt pans, and lagoons. For much of the twentieth century, it was regarded as a subspecies or synonym of P. sphenops, but morphological and genetic studies have confirmed its status as a distinct species. The molly is highly variable in size and color, with males ranging from 2.6 to 5.3 cm and females from 3.2 to 9.6 cm, and coloration varying from grayish-brown to yellow or orange in any given population. Marine fish are generally larger, stronger, and more colorful than freshwater specimens. Males' ability to develop an intense orange coloration may make the species attractive to aquarists. Forming shoals near the surface, mollies feed mainly on algae, detritus, and aquatic invertebrates, and are preyed upon by other fish and birds. Females produce live fry, giving the species an edge over killifish, with which it competes across its range. Successful reproduction depends on the availability of shelter for fry, most of which fall prey to adults. The species is drawn to freshwater habitats, which disappear in each dry season, killing freshwater populations; these habitats are recolonized from the sea when the rains return. (Full article...)

    A freshwater male

    Poecilia vandepolli, or Van de Poll's molly, is a poeciliid fish native to the Caribbean islands of Aruba, Bonaire, and Curaçao. It is one of the most common fish in its range, inhabiting fresh, brackish, salt, and hypersaline waters such as streams, ponds, bays, salt pans, and lagoons. For much of the twentieth century, it was regarded as a subspecies or synonym of P. sphenops, but morphological and genetic studies have confirmed its status as a distinct species. The molly is highly variable in size and color, with males ranging from 2.6 to 5.3 cm and females from 3.2 to 9.6 cm, and coloration varying from grayish-brown to yellow or orange in any given population. Marine fish are generally larger, stronger, and more colorful than freshwater specimens. Males' ability to develop an intense orange coloration may make the species attractive to aquarists.

    Forming shoals near the surface, mollies feed mainly on algae, detritus, and aquatic invertebrates, and are preyed upon by other fish and birds. Females produce live fry, giving the species an edge over killifish, with which it competes across its range. Successful reproduction depends on the availability of shelter for fry, most of which fall prey to adults. The species is drawn to freshwater habitats, which disappear in each dry season, killing freshwater populations; these habitats are recolonized from the sea when the rains return. (Full article...)
  • Image 6 The dwarf pufferfish (Carinotetraodon travancoricus), also known as the Malabar pufferfish, pygmy pufferfish, or pea pufferfish, is a small freshwater pufferfish endemic to Kerala and southern Karnataka in Southwest India. They are popular in aquaria for their bright colours and small size. At a maximum total length of 3.5 cm, dwarf pufferfish are one of the smallest pufferfish in the world. They closely resemble the related Carinotetraodon imitator, and the two can be difficult to distinguish. C. imitator was not recognised as a different species until 1999. Dwarf pufferfish dwell at the bottom of heavily vegetated waterways, predating small animals. Unlike other species of pufferfish, they are found in large groups in the wild. They breed throughout most of the year, with spawning pairs producing 1–5 eggs in 1–4 day intervals. Habitat loss and overharvesting for the aquarium trade threaten wild populations of dwarf pufferfish. (Full article...)

    The dwarf pufferfish (Carinotetraodon travancoricus), also known as the Malabar pufferfish, pygmy pufferfish, or pea pufferfish, is a small freshwater pufferfish endemic to Kerala and southern Karnataka in Southwest India. They are popular in aquaria for their bright colours and small size. At a maximum total length of 3.5 cm, dwarf pufferfish are one of the smallest pufferfish in the world. They closely resemble the related Carinotetraodon imitator, and the two can be difficult to distinguish. C. imitator was not recognised as a different species until 1999.

    Dwarf pufferfish dwell at the bottom of heavily vegetated waterways, predating small animals. Unlike other species of pufferfish, they are found in large groups in the wild. They breed throughout most of the year, with spawning pairs producing 1–5 eggs in 1–4 day intervals. Habitat loss and overharvesting for the aquarium trade threaten wild populations of dwarf pufferfish. (Full article...)
  • Image 7 Ballyhoo (Hemiramphus brasiliensis), a marine halfbeak Hemiramphidae is a family of fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar viviparous halfbeaks (family Zenarchopteridae) have often been included in this family. Though not commercially important themselves, these forage fish support artisanal fisheries and local markets worldwide. They are also fed upon by other commercially important predatory fishes, such as billfishes, mackerels, and sharks. (Full article...)

    Ballyhoo (Hemiramphus brasiliensis), a marine halfbeak

    Hemiramphidae is a family of fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar viviparous halfbeaks (family Zenarchopteridae) have often been included in this family.

    Though not commercially important themselves, these forage fish support artisanal fisheries and local markets worldwide. They are also fed upon by other commercially important predatory fishes, such as billfishes, mackerels, and sharks. (Full article...)
  • Image 8 The short-tail stingray or smooth stingray (Bathytoshia brevicaudata) is a common species of stingray in the family Dasyatidae. It occurs off southern Africa, typically offshore at a depth of 180–480 m (590–1,570 ft), and off southern Australia and New Zealand, from the intertidal zone to a depth of 156 m (512 ft). It is mostly bottom-dwelling in nature and can be found across a range of habitats from estuaries to reefs, but also frequently will swim into open water. One of the largest stingrays in the world, this heavy-bodied species can grow upwards of 2.1 m (6.9 ft) across and 350 kg (770 lb) in weight. Its plain-colored, diamond-shaped pectoral fin disc is characterized by a lack of dermal denticles even in adults, and white pores beside the head on either side. The body can have colors as well as dark grey or black with rows of white spots along each wing. Its tail is usually shorter than the disc and thick at the base. It is armed with large tubercles and a midline row of large thorns in front of the stinging spine which has the dorsal and ventral fin folds behind. The diet of the short-tail stingray consists of invertebrates and bony fishes, including burrowing and midwater species. It tends to remain within a relatively limited area throughout the year, preferring deeper waters during the winter, and is not known to perform long migrations. Large aggregations of rays form seasonally at certain locations, such as in the summer at the Poor Knight Islands off New Zealand. Both birthing and mating have been documented within the aggregations at Poor Knights. This species is aplacental viviparous, with the developing embryos sustained by histotroph ("uterine milk") produced by the mother. The litter size is typically 6 –10, but litter sizes of up to fifteen are not unheard of. (Full article...)

    The short-tail stingray or smooth stingray (Bathytoshia brevicaudata) is a common species of stingray in the family Dasyatidae. It occurs off southern Africa, typically offshore at a depth of 180–480 m (590–1,570 ft), and off southern Australia and New Zealand, from the intertidal zone to a depth of 156 m (512 ft). It is mostly bottom-dwelling in nature and can be found across a range of habitats from estuaries to reefs, but also frequently will swim into open water. One of the largest stingrays in the world, this heavy-bodied species can grow upwards of 2.1 m (6.9 ft) across and 350 kg (770 lb) in weight. Its plain-colored, diamond-shaped pectoral fin disc is characterized by a lack of dermal denticles even in adults, and white pores beside the head on either side. The body can have colors as well as dark grey or black with rows of white spots along each wing. Its tail is usually shorter than the disc and thick at the base. It is armed with large tubercles and a midline row of large thorns in front of the stinging spine which has the dorsal and ventral fin folds behind.

    The diet of the short-tail stingray consists of invertebrates and bony fishes, including burrowing and midwater species. It tends to remain within a relatively limited area throughout the year, preferring deeper waters during the winter, and is not known to perform long migrations. Large aggregations of rays form seasonally at certain locations, such as in the summer at the Poor Knight Islands off New Zealand. Both birthing and mating have been documented within the aggregations at Poor Knights. This species is aplacental viviparous, with the developing embryos sustained by histotroph ("uterine milk") produced by the mother. The litter size is typically 6 –10, but litter sizes of up to fifteen are not unheard of. (Full article...)
  • Image 9 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. This large species grows up to 3.8 m (12 ft) long. It generally inhabits water less than 92 m (302 ft) deep in a variety of habitats, from mangrove estuaries to coral reefs. A slow-moving predator feeding mainly on bony fishes, the sicklefin lemon shark seldom travels long distances and many individuals can be found year-round at certain locations. Like other members of its family, this species is viviparous, with females giving birth to no more than 13 pups every other year, following a gestation period of 10–11 months. Although they are potentially dangerous to humans and known to respond vigorously to any provocation, under normal circumstances, sicklefin lemon sharks are cautious and tend to retreat if approached. The IUCN has assessed this species as Endangered; its low reproductive productivity and rate of movement limits the capacity of depleted stocks to recover. Off India and Southeast Asia, this species has been severely depleted or extirpated by unregulated exploitation for its meat, fins, and liver oil. (Full article...)

    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. This large species grows up to 3.8 m (12 ft) long. It generally inhabits water less than 92 m (302 ft) deep in a variety of habitats, from mangrove estuaries to coral reefs.

    A slow-moving predator feeding mainly on bony fishes, the sicklefin lemon shark seldom travels long distances and many individuals can be found year-round at certain locations. Like other members of its family, this species is viviparous, with females giving birth to no more than 13 pups every other year, following a gestation period of 10–11 months. Although they are potentially dangerous to humans and known to respond vigorously to any provocation, under normal circumstances, sicklefin lemon sharks are cautious and tend to retreat if approached. The IUCN has assessed this species as Endangered; its low reproductive productivity and rate of movement limits the capacity of depleted stocks to recover. Off India and Southeast Asia, this species has been severely depleted or extirpated by unregulated exploitation for its meat, fins, and liver oil. (Full article...)
  • Image 10 at the Musicians Seamounts The sixgill stingray (Hexatrygon bickelli) is a species of stingray and the only extant member of the family Hexatrygonidae. Although several species of sixgill stingrays have been described historically, they may represent variations in a single, widespread species. This flabby, heavy-bodied fish, described only in 1980, is unique among rays in having six pairs of gill slits rather than five. Growing up to 1.7 m (5.6 ft) long, it has a rounded pectoral fin disc and a long, triangular, and flexible snout filled with a gelatinous substance. It is brownish above and white below, and lacks dermal denticles. Benthic in nature, the sixgill stingray is usually found in deep waters over upper continental slopes and seamounts at depths of 500–1,120 m (1,640–3,670 ft), the deepest-living stingray species known. It has been recorded from scattered locations in the Indo-Pacific from South Africa to Hawaii. This species probably uses its snout to probe for food in the bottom sediment. Its jaws are greatly protrusible, allowing it to capture buried prey. The sixgill stingray gives live birth, with litters of two to five pups. The IUCN has assessed this ray as Least Concern, because it faces minimal fishing pressure across most of its range. (Full article...)

    at the Musicians Seamounts

    The sixgill stingray (Hexatrygon bickelli) is a species of stingray and the only extant member of the family Hexatrygonidae. Although several species of sixgill stingrays have been described historically, they may represent variations in a single, widespread species. This flabby, heavy-bodied fish, described only in 1980, is unique among rays in having six pairs of gill slits rather than five. Growing up to 1.7 m (5.6 ft) long, it has a rounded pectoral fin disc and a long, triangular, and flexible snout filled with a gelatinous substance. It is brownish above and white below, and lacks dermal denticles.

    Benthic in nature, the sixgill stingray is usually found in deep waters over upper continental slopes and seamounts at depths of 500–1,120 m (1,640–3,670 ft), the deepest-living stingray species known. It has been recorded from scattered locations in the Indo-Pacific from South Africa to Hawaii. This species probably uses its snout to probe for food in the bottom sediment. Its jaws are greatly protrusible, allowing it to capture buried prey. The sixgill stingray gives live birth, with litters of two to five pups. The IUCN has assessed this ray as Least Concern, because it faces minimal fishing pressure across most of its range. (Full article...)
  • Image 11 The bigeye sand tiger (Odontaspis noronhai) is an extremely rare species of mackerel shark in the family Odontaspididae, with a possible worldwide distribution. A large, bulky species reaching at least 3.6 m (12 ft) in length, the bigeye sand tiger has a long bulbous snout, large orange eyes without nictitating membranes, and a capacious mouth with the narrow teeth prominently exposed. It can be distinguished from the similar smalltooth sand tiger (O. ferox) by its teeth, which have only one lateral cusplet on each side, and by its uniformly dark brown color. Inhabiting continental margins and oceanic waters at depths of 60–1,000 m (200–3,280 ft), the bigeye sand tiger may make vertical and horizontal migratory movements. It feeds on bony fishes and squid, and its sizable eyes and dark coloration suggest that it may spend most of its time in the mesopelagic zone. Reproduction is probably viviparous with oophagous embryos like in other mackerel shark species. This shark is caught incidentally by commercial fisheries, though so infrequently. (Full article...)

    The bigeye sand tiger (Odontaspis noronhai) is an extremely rare species of mackerel shark in the family Odontaspididae, with a possible worldwide distribution. A large, bulky species reaching at least 3.6 m (12 ft) in length, the bigeye sand tiger has a long bulbous snout, large orange eyes without nictitating membranes, and a capacious mouth with the narrow teeth prominently exposed. It can be distinguished from the similar smalltooth sand tiger (O. ferox) by its teeth, which have only one lateral cusplet on each side, and by its uniformly dark brown color.

    Inhabiting continental margins and oceanic waters at depths of 60–1,000 m (200–3,280 ft), the bigeye sand tiger may make vertical and horizontal migratory movements. It feeds on bony fishes and squid, and its sizable eyes and dark coloration suggest that it may spend most of its time in the mesopelagic zone. Reproduction is probably viviparous with oophagous embryos like in other mackerel shark species. This shark is caught incidentally by commercial fisheries, though so infrequently. (Full article...)
  • Image 12 The Japanese angelshark (Squatina japonica) is a species of angelshark, family Squatinidae, found in the northwestern Pacific Ocean off China, Japan, and Korea. It is a bottom-dwelling shark found in sandy habitats down to 300 m (980 ft) deep. This species has the flattened shape with wing-like pectoral and pelvic fins typical of its family, and grows to 1.5 m (4.9 ft) or more in length. Its two dorsal fins are placed behind the pelvic fins, and a row of large thorns occurs along its dorsal midline. Its upper surface is cryptically patterned, with numerous squarish dark spots on a brown background. Feeding on fishes, cephalopods, and crustaceans, the Japanese angelshark is a nocturnal ambush predator that spends most of the day lying still on the sea floor. This species gives birth to live young, which are sustained during gestation by yolk. The litter size varies from two to 10. The Japanese angelshark is not dangerous to humans unless provoked. It is fished in large numbers and used for meat and shagreen, a type of leather. (Full article...)

    The Japanese angelshark (Squatina japonica) is a species of angelshark, family Squatinidae, found in the northwestern Pacific Ocean off China, Japan, and Korea. It is a bottom-dwelling shark found in sandy habitats down to 300 m (980 ft) deep. This species has the flattened shape with wing-like pectoral and pelvic fins typical of its family, and grows to 1.5 m (4.9 ft) or more in length. Its two dorsal fins are placed behind the pelvic fins, and a row of large thorns occurs along its dorsal midline. Its upper surface is cryptically patterned, with numerous squarish dark spots on a brown background.

    Feeding on fishes, cephalopods, and crustaceans, the Japanese angelshark is a nocturnal ambush predator that spends most of the day lying still on the sea floor. This species gives birth to live young, which are sustained during gestation by yolk. The litter size varies from two to 10. The Japanese angelshark is not dangerous to humans unless provoked. It is fished in large numbers and used for meat and shagreen, a type of leather. (Full article...)
  • Image 13 The sparsely spotted stingaree (Urolophus paucimaculatus), also known as the white-spotted stingaree or Dixon's stingaree, is a species of stingray in the family Urolophidae, common off the southern Australian coast. Preferring sandy flats and seagrass beds, this benthic ray can be found from close to shore to a depth of at least 150 m (490 ft), and tends to occur deeper in the northern portion of its range. Reaching a length of 57 cm (22 in), this species has a broad, diamond-shaped pectoral fin disc that is typically plain gray in color above with a V-shaped marking between the eyes. Individuals from southerly waters also generally exhibit a smattering of small, dark-edged white spots. This ray is further characterized by a distinctively bell-shaped curtain of skin between the nostrils. Its tail has a skin fold running along either side and a leaf-shaped caudal fin, but no dorsal fin. Relatively inactive during daytime, the sparsely spotted stingaree preys mainly on crustaceans, and to a much lesser extent on polychaete worms and other small benthic organisms. It is aplacental viviparous, with the mother provisioning her young with histotroph ("uterine milk"). Life history differs between the eastern and western subpopulations: eastern females bear litters of up to six pups with a twelve-month gestation period, while western females bear litters of only one or two pups with a ten-month gestation period. Also, western rays mature later and live longer than eastern rays. The venomous sting of the sparsely spotted stingaree is potentially injurious to humans, and it has been reported to react aggressively if disturbed. The International Union for Conservation of Nature (IUCN) has listed it under Least Concern, as there is little fishing activity over the majority of its range. (Full article...)

    The sparsely spotted stingaree (Urolophus paucimaculatus), also known as the white-spotted stingaree or Dixon's stingaree, is a species of stingray in the family Urolophidae, common off the southern Australian coast. Preferring sandy flats and seagrass beds, this benthic ray can be found from close to shore to a depth of at least 150 m (490 ft), and tends to occur deeper in the northern portion of its range. Reaching a length of 57 cm (22 in), this species has a broad, diamond-shaped pectoral fin disc that is typically plain gray in color above with a V-shaped marking between the eyes. Individuals from southerly waters also generally exhibit a smattering of small, dark-edged white spots. This ray is further characterized by a distinctively bell-shaped curtain of skin between the nostrils. Its tail has a skin fold running along either side and a leaf-shaped caudal fin, but no dorsal fin.

    Relatively inactive during daytime, the sparsely spotted stingaree preys mainly on crustaceans, and to a much lesser extent on polychaete worms and other small benthic organisms. It is aplacental viviparous, with the mother provisioning her young with histotroph ("uterine milk"). Life history differs between the eastern and western subpopulations: eastern females bear litters of up to six pups with a twelve-month gestation period, while western females bear litters of only one or two pups with a ten-month gestation period. Also, western rays mature later and live longer than eastern rays. The venomous sting of the sparsely spotted stingaree is potentially injurious to humans, and it has been reported to react aggressively if disturbed. The International Union for Conservation of Nature (IUCN) has listed it under Least Concern, as there is little fishing activity over the majority of its range. (Full article...)
  • Image 14 The great hammerhead (Sphyrna mokarran) is the largest species of hammerhead shark, belonging to the family Sphyrnidae, attaining an average length of 4.6 m (15 ft) and reaching a maximum length of 6.2 m (20 ft). It is found in tropical and warm temperate waters worldwide, inhabiting coastal areas and the continental shelf. The great hammerhead can be distinguished from other hammerheads by the shape of its "hammer" (called the "cephalofoil"), which is wide with an almost straight front margin, its tall, sickle-shaped first dorsal fin, and its strongly falcated pelvic fins. A solitary, strong-swimming apex predator, the great hammerhead feeds on a wide variety of prey ranging from crustaceans and cephalopods, to bony fish, to smaller sharks. Observations of this species in the wild suggest that the cephalofoil functions to immobilize stingrays, a favored prey. This species has a viviparous mode of reproduction, bearing litters of up to 50 pups every two years. Although potentially dangerous, the great hammerhead rarely attacks humans and can sometimes behave inquisitively toward divers. This shark is heavily fished for its large fins, which are valuable on the Chinese market as the main ingredient of shark fin soup. As a result, great hammerhead populations are declining substantially worldwide, and it has been assessed as critically endangered by the International Union for Conservation of Nature (IUCN) as of 2019. (Full article...)

    The great hammerhead (Sphyrna mokarran) is the largest species of hammerhead shark, belonging to the family Sphyrnidae, attaining an average length of 4.6 m (15 ft) and reaching a maximum length of 6.2 m (20 ft). It is found in tropical and warm temperate waters worldwide, inhabiting coastal areas and the continental shelf. The great hammerhead can be distinguished from other hammerheads by the shape of its "hammer" (called the "cephalofoil"), which is wide with an almost straight front margin, its tall, sickle-shaped first dorsal fin, and its strongly falcated pelvic fins. A solitary, strong-swimming apex predator, the great hammerhead feeds on a wide variety of prey ranging from crustaceans and cephalopods, to bony fish, to smaller sharks. Observations of this species in the wild suggest that the cephalofoil functions to immobilize stingrays, a favored prey. This species has a viviparous mode of reproduction, bearing litters of up to 50 pups every two years.

    Although potentially dangerous, the great hammerhead rarely attacks humans and can sometimes behave inquisitively toward divers. This shark is heavily fished for its large fins, which are valuable on the Chinese market as the main ingredient of shark fin soup. As a result, great hammerhead populations are declining substantially worldwide, and it has been assessed as critically endangered by the International Union for Conservation of Nature (IUCN) as of 2019. (Full article...)
  • Image 15 Cretoxyrhina mantelli tooth from New Jersey, USA; Naturhistorisches Museum (Vienna) Cretoxyrhina (/krɪˌtɒksiˈrhaɪnə/; meaning 'Cretaceous sharp-nose') is an extinct genus of large mackerel shark that lived about 107 to 73 million years ago during the late Albian to late Campanian of the Late Cretaceous. The type species, C. mantelli, is more commonly referred to as the Ginsu shark, first popularized in reference to the Ginsu knife, as its theoretical feeding mechanism is often compared with the "slicing and dicing" when one uses the knife. Cretoxyrhina is traditionally classified as the likely sole member of the family Cretoxyrhinidae but other taxonomic placements have been proposed, such as within the Alopiidae and Lamnidae. Measuring up to 8 m (26 ft) in length and weighing around 5,000 kg (11,000 lb), Cretoxyrhina was one of the largest sharks of its time. Having a similar appearance and build to the modern great white shark, it was an apex predator in its ecosystem and preyed on a large variety of marine animals including mosasaurs, plesiosaurs, sharks and other large fish, pterosaurs, and occasionally dinosaurs. Its teeth, up to 8 cm (3.1 in) long, were razor-like and had thick enamel built for stabbing and slicing prey. Cretoxyrhina was also among the fastest-swimming sharks, with hydrodynamic calculations suggesting burst speeds of up to 70 km/h (43 mph). It has been speculated that Cretoxyrhina hunted by lunging at its prey at high speeds to inflict powerful blows, similar to the great white shark today, and relied on strong eyesight to do so. (Full article...)

    Cretoxyrhina mantelli tooth from New Jersey, USA; Naturhistorisches Museum (Vienna)

    Cretoxyrhina (/krɪˌtɒksiˈrhaɪnə/; meaning 'Cretaceous sharp-nose') is an extinct genus of large mackerel shark that lived about 107 to 73 million years ago during the late Albian to late Campanian of the Late Cretaceous. The type species, C. mantelli, is more commonly referred to as the Ginsu shark, first popularized in reference to the Ginsu knife, as its theoretical feeding mechanism is often compared with the "slicing and dicing" when one uses the knife. Cretoxyrhina is traditionally classified as the likely sole member of the family Cretoxyrhinidae but other taxonomic placements have been proposed, such as within the Alopiidae and Lamnidae.


    Measuring up to 8 m (26 ft) in length and weighing around 5,000 kg (11,000 lb), Cretoxyrhina was one of the largest sharks of its time. Having a similar appearance and build to the modern great white shark, it was an apex predator in its ecosystem and preyed on a large variety of marine animals including mosasaurs, plesiosaurs, sharks and other large fish, pterosaurs, and occasionally dinosaurs. Its teeth, up to 8 cm (3.1 in) long, were razor-like and had thick enamel built for stabbing and slicing prey. Cretoxyrhina was also among the fastest-swimming sharks, with hydrodynamic calculations suggesting burst speeds of up to 70 km/h (43 mph). It has been speculated that Cretoxyrhina hunted by lunging at its prey at high speeds to inflict powerful blows, similar to the great white shark today, and relied on strong eyesight to do so. (Full article...)

Selected fish –

Whale shark in the Andaman Sea around the Similan Islands

The whale shark (Rhincodon typus) is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. An individual with a length of 18.8 m (61.7 ft) 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 most massive 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...)

Did you know (auto-generated) -

  • ... that the critically endangered fish Quintana atrizona has not been seen in the wild since 2007–2008?
  • ... that some of the interior decoration of the Ernst-Haeckel-Haus is inspired by jellyfish?
  • ... that the director of a Lake Erie-based walleye fishing tournament defended two anglers accused of cheating until he found weights in their winning fish two years ago today?
  • ... that Hixxy and Sharkey created a schism in the UK rave music scene in 1995?
  • ... that Japanese businessman Yasuyoshi Kato used embezzled funds to support his wife, who bought twenty Arabian horses, several emus, llamas, potbellied pigs, miniature cattle, and nurse sharks?
  • ... that marmalade, mashed potato and fish knives were all used in the book Class to identify different British social classes?

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The following are images from various fish-related articles on Wikipedia.

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"So long, and thanks for all the fish!"

---Last sentence the dolphins sang to humans before they flew off to space, from The Hitchhiker's Guide to the Galaxy by Douglas Adams

List articles

For more lists, see Category:Lists of fishes

Topics

Ichthyology : Fish anatomy, Fish development, Fish diseases, Fish locomotion, Fish migration, Ichthyology terms, Limnology, Marine biology, Meristics, Oceanography, Spawning
Taxa : Chondrichthyes, Osteichthyes, Actinopterygii, Sarcopterygii, Chondrostei, Neopterygii, Holostei, Teleostei, Osteoglossomorpha, Elopomorpha, Clupeomorpha, Ostariophysi, Cyclosquamata, Scopelomorpha, Lampridiomorpha, Polymyxiomorpha, Paracanthopterygii, Acanthopterygii
Fishery : Angling, Aquaculture, Fishing, Fish as food, Fish farming, Fish market, Fisheries management, Fishing industry, Overfishing
Food fish : Anchovy, Barb, Basa fish, Bass, Carp, Catfish, Cod, Eel, Flatfish, Goby, Gourami, Haddock, Herring, Mackerel, Oily fish, Perch, Pollock, Salmon, Snapper, Snakehead, Sturgeon, Tilapia, Trout, Tuna, Whitefish
Fishkeeping : Aeration, Aquarium, Fish food, Marine aquarium, Reef aquarium, Brackish water aquarium
Ornamental fish : Angelfish(freshwater), Angelfish(marine), Barb, Blenny, Boxfish, Butterflyfish, Cichlid, Chromis, Clownfish, Corydoras, Damsel, Danio, Discus, Goby, Goldfish, Gourami, Koi, Lionfish, Live-bearer, Loach, Mbuna, Rainbowfish, Pufferfish, Rasbora, Seahorse, Siamese fighting fish, Suckermouth catfish, Tang, Tetra, Triggerfish, Wrasse
Others : Amphibious fish, Electric fish, Deep sea fish, Ichthys, Mermaid, Prehistoric fish, Ray, Shark, Walking fish

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  • Develop featured article: Ocean sunfish is in danger of losing its featured article status - improvement urgently needed.
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  • Picture request: Phreatobius cisternarum, Scoloplax, Nematogenys inermis, Chiapas catfish (Upload any non-copyrighted fish images to the appropriate section of Wikimedia Commons)
  • Identify images: Identify and move fish-related images to the appropriate sections of Wikimedia Commons, especially images of unidentified fish
  • Collaboration: Pacific jack mackerel (edit | talk | history | protect | delete | links | watch | logs | views)
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  • Other: Expand Fish anatomy and Fish locomotion, Create articles for the two missing families in the Perciformes (Bembropidae and Zanclorhynchidae). Merge GLAM/ARKive donated texts into articles about endangered species.

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    The Fish Portal: Mini Edition

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    See also

    For additional lists of marine life-related featured articles and good articles see:

    The Fish Quiz

    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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