The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial cells, known as hair cells, which respond to displacement caused by motion and transduce these signals into electrical impulses via excitatory synapses. Lateral lines play an important role in schooling behavior, predation, and orientation.
Early in the evolution of fish, some of the sensory organs of the lateral line were modified to function as the electroreceptors called ampullae of Lorenzini. The lateral line system is ancient and basal to the vertebrate clade, as it is found in fishes that diverged over 400 million years ago. (Full article...)
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The short-tail stingray or smooth stingray (Bathytoshia brevicaudata) is a common species of stingray in the familyDasyatidae. 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...)
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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 common torpedo (Torpedo torpedo), also known as ocellate torpedo or eyed electric ray, is a species of electric ray in the family Torpedinidae. It is found in the Mediterranean Sea and the eastern Atlantic Ocean from the Bay of Biscay to Angola, and is a benthic fish typically encountered over soft substrates in fairly shallow, coastal waters. Growing to 60 cm (24 in) long, this species has a nearly circular pectoral fin disc and a short, thick tail with two dorsal fins of nearly equal size and a large caudal fin. It can be identified by the prominent blue spots on its back, which usually number five but may vary from zero to nine, as well as by the small knobs on the rims of its spiracles.
For attack and defense, the common torpedo can deliver a strong electric shock of up to 200 volts. It is a solitary, nocturnalambush predator that feeds mainly on bony fishes and crustaceans. This species is aplacental viviparous, with the developing embryos nourished by yolk and histotroph ("uterine milk") produced by the mother. Females produce litters of up to 28 young every year in late summer or autumn, after a gestation period of 4–8 months; the specifics vary between geographical regions. The common torpedo's shock is painful but otherwise of little danger to humans. Its electrogenic properties led it to be used in medicine by the ancient Greeks and Romans. In modern times, it has no economic value and is mostly discarded when caught as bycatch in fisheries. The impact of fishing on its population is uncertain, and the International Union for Conservation of Nature (IUCN) has listed it as Vulnerable. (Full article...)
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The Australian blacktip shark (Carcharhinus tilstoni) is a species of requiem shark, in the family Carcharhinidae, endemic to northern and eastern Australia. Favoring the upper and middle parts of the water column, it can be found from the intertidal zone to a depth of 50 m (160 ft). Appearance-wise this species is virtually identical to the common blacktip shark (C. limbatus), from which it can be reliably distinguished only by its lower vertebra number and by genetic markers. Generally reaching 1.5–1.8 m (4.9–5.9 ft) in length, it is a fairly stout-bodied, bronze-colored shark with a long snout and black-tipped fins.
Primarily piscivorous, the Australian blacktip shark forms large groups of similar size and sex that tend to remain within a local area. It exhibits viviparity, meaning that the unborn young are provisioned through a placental connection. There is a well-defined annual reproductive cycle with mating occurring in February and March. Females bear one to six pups around January of the following year, after a 10-month gestation period. The Australian blacktip shark is among the sharks most commonly caught by northern Australian commercial fisheries. It is mainly valued for its meat, which is sold as "flake". This species was an important catch of a Taiwanesegillnet fishery that operated from 1974 to 1986, and of the Australian Northern Shark Fishery that continues to the present day. As current fishing levels are not thought to threaten this shark's population, the International Union for Conservation of Nature (IUCN) has assessed it as Least Concern. (Full article...)
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The night shark (Carcharhinus signatus) is a species of requiem shark, in the familyCarcharhinidae, found in the temperate and tropical waters of the Atlantic Ocean. An inhabitant of the outer continental shelf and upper continental slope, this shark most commonly occurs at depths of 50–600 m (160–1,970 ft) and conducts a diel vertical migration, spending the day in deeper water and moving into shallower waters at night. Off northeastern Brazil, large numbers congregate around seamounts of varying depths. A slender, streamlined species, the night shark typically reaches a length of 2 m (6.6 ft). It can be identified by its long, pointed snout and large, green eyes (when alive), and is dark grayish blue or brown above and white below.
Night sharks are quick, nocturnally active, schoolingpredators that feed mainly on small bony fishes and squid. Reproduction is viviparous as with the other members of its family; females mate during the summer and give birth to litters of usually 12–18 pups after a gestation period of a year. This deepwater species is not known to pose a danger to humans. It is caught incidentally by commercialtuna and swordfishlongline fisheries in the western Atlantic, and also by a targeted longline fishery operating off northeastern Brazil. The night shark is highly valued for its fins, and additionally as a source of meat, liver oil, and fishmeal. However, most sharks caught off northeastern Brazil have been found to contain unsafe concentrations of mercury. (Full article...)
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The porbeagle or porbeagle shark (Lamna nasus) is a species of mackerel shark in the familyLamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. In the North Pacific, its ecological equivalent is the closely related salmon shark (L. ditropis). It typically reaches 2.5 m (8.2 ft) in length and a weight of 135 kg (298 lb); North Atlantic sharks grow larger than Southern Hemisphere sharks and differ in coloration and aspects of life history. Gray above and white below, the porbeagle has a very stout midsection that tapers towards the long, pointed snout and the narrow base of the tail. It has large pectoral and first dorsal fins, tiny pelvic, second dorsal, and anal fins, and a crescent-shaped caudal fin. The most distinctive features of this species are its three-cusped teeth, the white blotch at the aft base of its first dorsal fin, and the two pairs of lateral keels on its tail.
The porbeagle is an opportunistic hunter that preys mainly on bony fishes and cephalopods throughout the water column, including the bottom. Most commonly found over food-rich banks on the outer continental shelf, it makes occasional forays both close to shore and into the open ocean to a depth of 1,360 m (4,460 ft). It also conducts long-distance seasonal migrations, generally shifting between shallower and deeper water. The porbeagle is fast and highly active, with physiological adaptations that enable it to maintain a higher body temperature than the surrounding water. It can be solitary or gregarious, and has been known to perform seemingly playful behavior. This shark is aplacental viviparous with oophagy, developing embryos being retained within the mother's uterus and subsisting on non-viable eggs. Females typically bear four pups every year. (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 dwarf pufferfish (Carinotetraodon travancoricus), also known as the Malabar pufferfish, pygmy pufferfish, or pea pufferfish, is a small freshwaterpufferfishendemic 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...)
Manta rays are large rays belonging to the genusMobula (formerly its own genusManta). The larger species, M. birostris, reaches 7 m (23 ft) in width, while the smaller, M. alfredi, reaches 5.5 m (18 ft). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes (stingrays and relatives) and are placed in the familyMyliobatidae (eagle rays). They have the largest brains and brain to body ratio of all fish, and can pass the mirror test.
Mantas are found in warm temperate, subtropical and tropical waters. Both species are pelagic; M. birostrismigrates across open oceans, singly or in groups, while M. alfredi tends to be resident and coastal. They are filter feeders and eat large quantities of zooplankton, which they gather with their open mouths as they swim. However, research suggests that the majority of their diet (73%) comes from mesopelagic sources. Gestation lasts over a year and mantas give birth to live pups. Mantas may visit cleaning stations for the removal of parasites. Like whales, they breach for unknown reasons. (Full article...)
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The Murray cod (Maccullochella peelii) is a large Australian predatory freshwater fish of the genus Maccullochella in the family Percichthyidae. Although the species is called a cod in the vernacular, it is not related to the Northern Hemisphere marine cod (Gadus) species. The Murray cod is an important part of Australia's vertebrate wildlife—as an apex predator in the Murray-Darling River system—and also significant in Australia's human culture. The Murray cod is the largest exclusively freshwater fish in Australia, and one of the largest in the world. Other common names for Murray cod include cod, greenfish, goodoo, Mary River cod, Murray perch, ponde, pondi and Queensland freshwater cod.
The scientific name of Murray cod derives from an early Australian fish researcher Allan Riverstone McCulloch and the river from which the explorer Major Mitchell first scientifically described the species, the Peel River. This was for a number of years changed to M. peelii peelii to differentiate Murray cod from Mary River cod, which were designated as a subspecies of Murray cod. However, as of 2010, Mary River cod have been raised to full species status (M. mariensis), thus Murray cod have reverted simply to M. peelii. (Full article...)
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Bowfin in aquarium
The bowfin (Amia calva) is a bony fish, native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being one of only two surviving species of the Halecomorphi, a group of fish that first appeared during the Early Triassic, around 250 million years ago. The bowfin is often considered a "primitive fish" because they have retained some morphological characteristics of their early ancestors. It is one of two species in the genus Amia, along with Amia ocellicauda, the eyespot bowfin. The closest living relatives of bowfins are gars, with the two groups being united in the clade Holostei.
Bowfins are demersal freshwater piscivores, commonly found throughout much of the eastern United States, and in southern Ontario and Quebec. Fossil deposits indicate Amiiformes were once widespread in both freshwater and marine environments across North and South America, Europe, Asia, and Africa. Now, their range is limited to much of the eastern United States and adjacent southern Canada, including the drainage basins of the Mississippi River, Great Lakes, and various rivers exiting in the Eastern Seaboard or Gulf of Mexico. Their preferred habitat includes vegetated sloughs, lowland rivers and lakes, swamps, and backwater areas; they are also occasionally found in brackish water. They are stalking, ambush predators known to move into the shallows at night to prey on fish and aquatic invertebrates such as crawfish, mollusks, and aquatic insects. (Full article...)
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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 grey reef shark or gray reef shark (Carcharhinus amblyrhynchos, sometimes misspelled amblyrhynchus or amblyrhinchos) is a species of requiem shark, in the familyCarcharhinidae. One of the most common reef sharks in the Indo-Pacific, it is found as far east as Easter Island and as far west as South Africa. This species is most often seen in shallow water near the drop-offs of coral reefs. It has the typical "reef shark" shape, with a broad, round snout and large eyes. It can be distinguished from similar species by the plain or white-tipped first dorsal fin, the dark tips on the other fins, the broad, black rear margin on the tail fin, and the lack of a ridge between the dorsal fins. Most individuals are less than 1.88 m (6.2 ft) long.
The grey reef shark is a fast-swimming, agile predator that feeds primarily on free-swimming bony fishes and cephalopods. Its aggressive demeanor enables it to dominate many other shark species on the reef, despite its moderate size. Many grey reef sharks have a home range on a specific area of the reef, to which they continually return. However, they are social rather than territorial. During the day, these sharks often form groups of five to 20 individuals near coral reef drop-offs, splitting up in the evening as the sharks begin to hunt. Adult females also form groups in very shallow water, where the higher water temperature may accelerate their growth or that of their unborn young. Like other members of its family, the grey reef shark is viviparous, meaning the mother nourishes her embryos through a placental connection. Litters of one to six pups are born every other year. (Full article...)
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The bignose shark (Carcharhinus altimus) is a species of requiem shark, in the family Carcharhinidae. Distributed worldwide in tropical and subtropical waters, this migratory shark frequents deep waters around the edges of the continental shelf. It is typically found at depths of 90–430 m (300–1,410 ft), though at night it may move towards the surface or into shallower water. The bignose shark is plain-colored and grows to at least 2.7–2.8 m (8.9–9.2 ft) in length. It has a long, broad snout with prominent nasal skin flaps, and tall, triangular upper teeth. Its pectoral fins are long and almost straight, and there is a ridge on its back between the two dorsal fins.
While regarded as one of the largest and most powerful predators to have ever lived, megalodon is only known from fragmentary remains, and its appearance and maximum size are uncertain. Scientists differ on whether it would have more closely resembled a stockier version of the great white shark (Carcharodon carcharias), the basking shark (Cetorhinus maximus) or the sand tiger shark (Carcharias taurus). The most recent estimate with the least error range suggests a maximum length estimate up to 20.3 meters (67 ft), although the modal lengths are estimated at 10.5 meters (34 ft). Their teeth were thick and robust, built for grabbing prey and breaking bone, and their large jaws could exert a bite force of up to 108,500 to 182,200 newtons (24,390 to 40,960 lbf). (Full article...)
... that Phallichthys (literally 'penis fish') species are so called because the males have "comparatively huge" sex appendages?
... that Eyvindur P. Eiríksson has addressed modern alienation and man's relationship with nature through pagan poetry and a book about a fishing trawler?
Image 4Surgeonfish 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 5Most 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 11Most 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 12Lanternfish 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 13Scale diagram of the layers of the pelagic zone (from Pelagic fish)
Image 14Cod-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 15Red 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 17The 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 20The 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 23Humans seldom encounter frilled sharks alive, so they pose little danger (though scientists have accidentally cut themselves examining their teeth). (from Deep-sea fish)
Image 27Long-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 28Coral 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 34The 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 39The 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 40Some flatfish can camouflage themselves on the ocean floor (from Demersal fish)
Image 41World distribution of plankton (from Coastal fish)
Image 55Many 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 57Young, 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 68Shortfin 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 77The 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 79In 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)
Mudskippers, such as this Periophthalmodon septemradiatus, are uniquely adapted to a completely amphibious lifestyle. They are active when out of water, feeding and interacting with one another, as well as defending their territories.
The round ribbontail ray (Taeniura meyeni) is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific region. Reaching 1.8 m (6 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 single venomous spine. The ray is well-camouflaged when lying on the seabed; it is largely nocturnal, and preys on molluscs, crustaceans and bony fish. Mature females bear litters of up to seven pups, which are fed during gestation on "uterine milk", a product secreted by the walls of the oviduct. This round ribbontail ray was photographed in Lakshadweep, India.
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 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 40 ft (12 m) at Bari Reef, Bonaire.
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.
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 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 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.
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 310 m (130 and 1,020 ft). It is a medium-sized shark with a saw-like flattened snout which measures up to thirty percent of its body size.
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 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.
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.
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