FishA fish (: fish or fishes) is an aquatic, craniate, gill-bearing animal that lacks limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period.
TeleostTeleostei (ˌtɛliˈɒstiaɪ; Greek teleios "complete" + osteon "bone"), members of which are known as teleosts (ˈtɛliɒsts,_ˈtiːli-), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, and contains 96% of all extant species of fish. Teleosts are arranged into about 40 orders and 448 families. Over 26,000 species have been described. Teleosts range from giant oarfish measuring or more, and ocean sunfish weighing over , to the minute male anglerfish Photocorynus spiniceps, just long.
Electroreception and electrogenesisElectroreception and electrogenesis are the closely related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes (most famously the electric eel, which is not actually an eel but a knifefish) to stun prey. The capabilities are found almost exclusively in aquatic or amphibious animals, since water is a much better conductor of electricity than air.
Chinese paddlefishThe Chinese paddlefish (Psephurus gladius; : literal translation: "white sturgeon"), also known as the Chinese swordfish, is an extinct species of fish that was formerly native to the Yangtze and Yellow River basins in China. With records of specimens over and possibly in length, it was one of the largest species of freshwater fish. It was the only species in the genus Psephurus and one of two recent species of paddlefish (Polyodontidae), the other being the American paddlefish (Polyodon spathula).
Fish finFins are distinctive anatomical features composed of bony spines or rays protruding from the body of Actinopterygii and Chondrichthyes fishes. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim.
Rostrum (anatomy)Rostrum (from Latin rostrum, meaning beak) is a term used in anatomy for a number of phylogenetically unrelated structures in different groups of animals. In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes. It is generally a rigid structure, but can be connected by a hinged joint, as seen in Leptostraca. Among insects, the rostrum is the name for the piercing mouthparts of the order Hemiptera as well as those of the snow scorpionflies, among many others.
SturgeonAutomatic taxobox | name = Sturgeon | image = Acipenser oxyrhynchus.jpg | image_caption = Atlantic sturgeon(Acipenser oxyrinchus oxyrinchus) | fossil_range = | taxon = Acipenseridae | authority = Bonaparte, 1831 | subdivision_ranks = Genera | subdivision = *†Protoscaphirhynchus †Engdahlichthys †Anchiacipenser †Priscosturion Acipenser (paraphyletic) Huso Scaphirhynchus Pseudoscaphirhynchus Sturgeon is the common name for the 28 species of fish belonging to the family Acipenseridae.
Fish scaleA fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term scale derives from the Old French escale, meaning a shell pod or husk. Scales vary enormously in size, shape, structure, and extent, ranging from strong and rigid armour plates in fishes such as shrimpfishes and boxfishes, to microscopic or absent in fishes such as eels and anglerfishes.
American paddlefishThe American paddlefish (Polyodon spathula, also known as a Mississippi paddlefish, spoon-billed cat, or spoonbill) is a species of ray-finned fish. It is the last living species of paddlefish (Polyodontidae). This family is most closely related to the sturgeons; together they make up the order Acipenseriformes, which are one of the most primitive living groups of ray-finned fish. Fossil records of other paddlefish species date back 125 million years to the Early Cretaceous, with records of Polyodon extending back 65 million years to the early Paleocene.
Fish jawMost bony fishes have two sets of jaws made mainly of bone. The primary oral jaws open and close the mouth, and a second set of pharyngeal jaws are positioned at the back of the throat. The oral jaws are used to capture and manipulate prey by biting and crushing. The pharyngeal jaws, so-called because they are positioned within the pharynx, are used to further process the food and move it from the mouth to the stomach. Cartilaginous fishes, such as sharks and rays, have one set of oral jaws made mainly of cartilage.
