The milk shark (Rhizoprionodon acutus) is a species of requiem shark, and part of the familyCarcharhinidae, whose common name comes from an Indian belief that consumption of its meat promotes lactation. The largest and most widely distributed member of its genus, the milk shark typically measures 1.1 m (3.6 ft) long, and can be found in coastal tropical waters throughout the eastern Atlantic and the Indo-Pacific regions. Occurring from the surface to a depth of 200 m (660 ft), this species is common near beaches and in estuaries, and has been recorded swimming up rivers in Cambodia. Juveniles are known to inhabit tidal pools and seagrass meadows. The milk shark has a slender body with a long, pointed snout and large eyes, and is a nondescript gray above and white below. This shark can be distinguished from similar species in its range by the long furrows at the corners of its mouth, and seven to 15 enlarged pores just above them.
The frilled shark (Chlamydoselachus anguineus), also known as the lizard shark, is one of the two extant species of shark in the familyChlamydoselachidae (the other is the southern African frilled shark (Chlamydoselachus africana)). The frilled shark is considered a living fossil, because of its primitive, anguilliform (eel-like) physical traits, such as a dark-brown color, amphistyly (the articulation of the jaws to the cranium), and a 2.0 m (6.6 ft)–long body, which has dorsal, pelvic, and anal fins located towards the tail. The common name, frilled shark, derives from the fringed appearance of the six pairs of gill slits at the shark's throat.
The two species of frilled shark are distributed throughout regions of the Atlantic and the Pacific oceans, usually in the waters of the outer continental shelf and of the upper continental slope, where the sharks usually live near the ocean floor, near biologically productive areas of the ecosystem. To live on a diet of cephalopods, smaller sharks, and bony fish, the frilled shark practices diel vertical migration to feed at night at the surface of the ocean. When hunting food, the frilled shark curls its tail against a rock and moves like an eel, bending and lunging to capture and swallow whole prey with its long and flexible jaws, which are equipped with 300 recurved, needle-like teeth. (Full article...)
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The Japanese sleeper ray (Narke japonica) is a species of electric ray in the familyNarkidae. It is common in the inshore and offshore waters of the northwestern Pacific Ocean from southern Japan to southern China. Growing up to 40 cm (16 in) long, the Japanese sleeper ray has a nearly circular pectoral fin disc colored reddish to chocolate brown above, sometimes with darker or lighter spots, and lighter brown below. The spiracles behind its small eyes have raised, smooth rims. Its short and muscular tail bears a single dorsal fin positioned aft of the rounded pelvic fins, and terminates in a large caudal fin.
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 36–38 cm (14–15 in) and 55–61 cm (22–24 in) 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...)
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The nursehound (Scyliorhinus stellaris), also known as the large-spotted dogfish, greater spotted dogfish or bull huss, is a species of catshark, belonging to the familyScyliorhinidae, found in the northeastern Atlantic Ocean. It is generally found among rocks or algae at a depth of 20–60 m (66–197 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fins placed far back. It shares its range with the more common and closely related small-spotted catshark (S. canicula), which it resembles in appearance but can be distinguished from, in having larger spots and nasal skin flaps that do not extend to the mouth.
Nursehounds have nocturnal habits and generally hide inside small holes during the day, often associating with other members of its species. A benthicpredator, it feeds on a range of bony fishes, smaller sharks, crustaceans, and cephalopods. Like other catsharks, the nursehound is oviparous in reproduction. Females deposit large, thick-walled egg cases, two at a time, from March to October, securing them to bunches of seaweed. The eggs take 7–12 months to hatch. Nursehounds are marketed as food in several European countries under various names, including "flake", "catfish", "rock eel", and "rock salmon". It was once also valued for its rough skin (called "rubskin"), which was used as an abrasive. The International Union for Conservation of Nature (IUCN) has assessed the nursehound as Vulnerable, as its population in the Mediterranean Sea seems to have declined substantially from overfishing. (Full article...)
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The sharptooth houndshark or spotted gully shark (Triakis megalopterus) is a species of houndshark in the family Triakidae found in shallow inshore waters from southern Angola to South Africa. Favoring sandy areas near rocky reefs and gullies, it is an active-swimming species that usually stays close to the bottom. This robust shark reaches 1.7 m (5.6 ft) in length and has characteristically large, rounded fins; the pectoral fins in particular are broad and sickle-shaped in adults. It also has a short, blunt snout and long furrows around its mouth. This species is gray or bronze in color above, with variable amounts of black spotting.
Mainly active at night, the sharptooth houndshark feeds mostly on crustaceans, bony fishes, and cephalopods. It has been observed gathering in groups in shallow water during summertime, possibly for reproductive purposes. This species is aplacental viviparous, meaning that the unborn young are sustained mainly by yolk. Females give birth to 6–12 pups between late May and August, on a 2- or 3-year cycle. The sharptooth houndshark is often hooked by recreational anglers, and some are also captured on commercial bottom longlines. Because of its small range and low growth and reproductive rates, it is very vulnerable to overfishing. The International Union for Conservation of Nature has listed this species as least concern. (Full article...)
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The sand devil or Atlantic angel shark (Squatina dumeril) is a species of angelshark, family Squatinidae, native to the northwestern Atlantic Ocean. It occurs off the eastern United States, in the northern Gulf of Mexico, and possibly in parts of the Caribbean Sea. This bottom-dwelling shark is found in shallow inshore waters in summer and fall, and deep offshore waters in winter and spring. The sand devil's flattened body and enlarged pectoral and pelvic fins give it a ray-like appearance. There is a band of enlarged thorns running along the middle of its back. It is gray or brown in color, with scattered small dark spots. This species reaches 1.2–1.5 m (3.9–4.9 ft) in length.
The diet of the sand devil consists mainly of small teleost fishes and squid, which are captured via ambush attack. This species is viviparous, with the unborn young nourished by their yolk sacs. Females have a multi-year reproductive cycle and give birth to 4–25 pups in spring or early summer, following a 12-month gestation period. The sand devil is not aggressive, but may attempt to bite if harassed or captured. Though not valued economically, it is caught incidentally by commercialbottom trawlfisheries. (Full article...)
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The round ribbontail ray or blotched fantail ray, (Taeniurops meyeni) is a species of stingray in the familyDasyatidae, found throughout the nearshore waters of the tropicalIndo-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.
The silvertip shark (Carcharhinus albimarginatus) is a large species of requiem shark, in the familyCarcharhinidae, with a fragmented distribution throughout the tropicalIndian and Pacific Oceans. It is often encountered around offshore islands and coral reefs, and has been known to dive to a depth of 800 m (2,600 ft). The silvertip shark resembles a larger and bulkier grey reef shark (C. amblyrhynchos), but can be easily identified by the prominent white margins on its fins. It attains a maximum length of 3 m (10 ft).
An aggressive, powerful apex predator, the silvertip shark feeds on a wide variety of bony fishes, as well as eagle rays, smaller sharks, and cephalopods. This species dominates other requiem sharks of equal size when competing for food, and larger individuals are often heavily scarred from conflicts with others of its species. As with other members of its family, the silvertip shark is viviparous, with females giving birth to one to 11 pups in the summer. Silvertip sharks are regarded as potentially dangerous to humans, as they often approach divers quite closely. This slow-reproducing species is taken by commercial fisheries for its meat, fins, skin, cartilage, and jaws and teeth, which has apparently led to local population declines or extirpations. (Full article...)
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The blackmouth catshark (Galeus melastomus) is a species of catshark, and part of the familyScyliorhinidae, common in the northeastern Atlantic Ocean from Iceland to Senegal, including the Mediterranean Sea. It is typically found over the continental slope at depths of 150–1,400 m (490–4,590 ft), on or near muddy bottoms. The youngest sharks generally inhabit shallower water than the older juveniles and adults. This slim-bodied species is characterized by the black interior of its mouth, a marbled pattern of pale-edged brownish saddles or blotches along its back and tail, and a prominent saw-toothed crest of enlarged dermal denticles along the upper edge of its caudal fin. It reaches lengths of 50–79 cm (20–31 in), with sharks in the Atlantic growing larger than those in the Mediterranean.
Slow-swimming but active, the blackmouth catshark is a generalist that preys on a wide variety of crustaceans, cephalopods, and fishes. Its visual and electroreceptive systems are adept at tracking moving, bioluminescent prey. This species is oviparous, with females producing batches of up to 13 egg cases throughout the year. Because of its abundance, the blackmouth catshark forms a substantial part of the bycatch of deepwater commercial fisheries across much of its range. It has low economic value and is usually discarded, though the largest sharks may be marketed for meat and leather. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern, as there is no indication that its numbers have declined despite fishing pressure. (Full article...)
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The tiger catshark (Halaelurus natalensis) is a species of catshark, belonging to the familyScyliorhinidae. It is found over sandy areas and near reef peripheries off South Africa and perhaps Mozambique, from close to shore to usually no deeper than 100 m (330 ft). Reaching a length of 50 cm (20 in), this small, slim shark has a broad, flattened head with an upturned snout tip. It can additionally be identified by its dorsal colour pattern of ten dark brown saddles on a yellowish brown background.
The queen angelfish (Holacanthus ciliaris), also known as the blue angelfish, golden angelfish, or yellow angelfish, is a species of marine angelfish found in the western Atlantic Ocean. It is a benthic (ocean floor) warm-water species that lives in coral reefs. It is recognized by its blue and yellow coloration and a distinctive spot or "crown" on its forehead. This crown distinguishes it from the closely related and similar-looking Bermuda blue angelfish (Holacanthus bermudensis), with which it overlaps in range and can interbreed.
Adult queen angelfish are selective feeders and primarily eat sponges. Their social structure consists of harems which include one male and up to four females. They live within a territory where the females forage separately and are tended to by the male. Breeding in the species occurs near a full moon. The transparent eggs float in the water until they hatch. Juveniles of the species have different coloration than adults and act as cleaner fish. (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 170 m (560 ft); smaller sharks frequent sand and seagrasshabitat and shift to coral reefs as they grow older. A slim, drab species reaching a length of 1.1 m (3.6 ft), 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 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, and by its tall, sickle-shaped first dorsal fin. 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...)
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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 mangroveestuaries 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 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 linescale 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 bivalvemolluscs. 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...)
... that the Tellico Dam project was controversial for its acquisition of farmland for real estate development, loss of Native American sites, and damaging an endangered fish habitat?
... that the blind cave eel is the longest cavefish in Australia?
... that the New Zealand fishing company Sealord Group is half-owned by iwi?
... that the historical lands and fishing grounds of the Skinpah were buried underwater by the construction of The Dalles Dam?
... that Kaʻelepulu Pond, formerly a 200-to-400-acre (81 to 162 ha) Hawaiian fish pond, is now about 95 acres (38 ha) and polluted after having been partially filled in for a housing development?
Image 2Surgeonfish 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 13Coral 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 14Most 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 19Profile illustrating the shelf, slope and rise (from Demersal fish)
Image 20Shortfin 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 22Areas of upwelling in red (from Pelagic fish)
Image 23Bigeye tuna cruise the epipelagic zone at night and the mesopelagic zone during the day (from Deep-sea fish)
Image 24Cod-like fishes, like this morid cod have a barbel (fleshy filament) on their lower jaw which they use to detect prey buried in the sand or mud. (from Coastal fish)
Image 26The daggertooth paralyses other mesopelagic fish when it bites them with its dagger-like teeth (from Deep-sea fish)
Image 27The humpback anglerfish is a bathypelagic ambush predator, which attracts prey with a bioluminescent lure. It can ingest prey larger than itself, which it swallows with an inrush of water when it opens its mouth. (from Pelagic fish)
Image 32Many 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 34The rattail Coryphaenoides armatus (abyssal grenadier) on the Davidson Seamount at a depth of 2,253 metres (7,392 ft). (from Deep-sea fish)
Image 35Scale diagram of the layers of the pelagic zone (from Pelagic fish)
Image 36Red snapper, are generalized reef feeders with standard jaw and mouth structures that allow them to eat almost anything, though they prefer small fish and crustaceans. (from Coral reef fish)
Image 37Some flatfish can camouflage themselves on the ocean floor (from Demersal fish)
Image 40The stoplight loosejaw has a lower jaw one-quarter as long as its body. The jaw has no floor and is attached only by a hinge and a modified tongue bone. Large fang-like teeth in the front are followed by many small barbed teeth. (from Deep-sea fish)
Image 41Herring reflectors are nearly vertical for camouflage from the side. (from Pelagic fish)
Image 43The 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 44Long-snouted lancetfish. Lancetfish are ambush predators which spend all their time in the mesopelagic zone. They are among the largest mesopelagic fishes (up to 2 m). (from Deep-sea fish)
Image 45The 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 47Lanternfish 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)
Image 48Most 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 50Young, 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)
Image 69In 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 70Scale diagram of the layers of the pelagic zone (from Deep-sea fish)
Image 76The stoplight loosejaw is also one of the few fishes that produce red bioluminescence. As most of their prey cannot perceive red light, this allows it to hunt with an essentially invisible beam of light. (from Deep-sea fish)
Image 77Humans seldom encounter frilled sharks alive, so they pose little danger (though scientists have accidentally cut themselves examining their teeth). (from Deep-sea fish)
The mandarinfish (Synchiropus splendidus, not to be confused with the similarly named mandarin fish) is a small (~6 cm or 2.4 in), brightly-colored member of the dragonet family, popular in the saltwater aquarium trade. The mandarinfish is native to the Western Pacific, ranging approximately from the Ryukyu Islands south to Australia.
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.
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.
Bryaninops yongei is a benthic species of goby widely distributed throughout the tropical and subtropical waters of the Indian Ocean; it is commonly found living in and around coral. Although this species was discovered in 1906, its ability to propel itself quickly to escape predators makes it difficult to study.
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 45 cm (ca. 18 in) and a mass of 1.6 kg (3.5 lb).
A plate with fossils of Pseudostacus sp. (lobster, left) and Diplomystus birdii (fish, right), from the Hakel paleontological formation in Lebanon. The paleontological sites of Lebanon contain deposits of some of the best-preserved fossils in the world, and include some species found nowhere else. The most famous of these is the Lebanese lagerstätten of the Late Cretaceous age.
Icefish are a type of Antarctic fish belonging to various families, including the Channichthyidae family. They have no haemoglobin and their blood is transparent. They feed on krill, copepods, and other fish. Icefish rely on well-oxygenated water and absorb oxygen directly through the skin as they lack red blood cells.
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 giant grouper (Epinephelus lanceolatus), shown here with a school of golden trevally, is the largest bony fish found in coral reefs, and the aquatic emblem of Queensland, Australia. The species can grow as large as 2.7 meters (9 ft) long, weighing up to 400 kg (880 lb). They are fairly common in shallow waters and feed on a variety of marine life, including small sharks and juvenile sea turtles.
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 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.
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".
The Eurasian ruffe (Gymnocephalus cernua) is a species of freshwater fish found in temperate regions of Europe and Asia. The aggressive fish is known to reproduce rapidly, leading to problems when it is introduced to foreign bodies of water.
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.
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.
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