Select another group Birds Bryozoans Crustaceans Fish Jellies Mammals Molluscs Plants Reptiles Segmented Worms Sponges Starfish & urchins Select a fish __________________ **Bony fish** __________________ Amberjack Anchoveta Angler fish Anoplogaster/    Fangtooth Anthias/    Sea goldie Atlantic herring Atlantic mackerel Atlantic sailfish Atlantic salmon Bicolour blenny Big-eye trevally Bigeye tuna Blackdevil angler Blackfin icefish Blacksmith Black triggerfish/    Black durgeon Blackspot snapper Blackspotted sweetlips Bluebanded goby Blue fusilier Blue marlin Bluefin tuna Bluestreak cleaner wrasse Bonefish Bonito Brown surgeonfish Bumphead parrotfish Cabezon California sheephead wrasse Capelin Chevron barracuda Cod Convict tang Coral grouper    Coral hind Dragonfish European eel Giant farmer fish/ Lagoon damselfish Flag cabrilla Flounder Flying fish Garibaldi Giant kelpfish Glassfish/    Golden sweeper Grenadier/    Rat-tail Gulper eel/    Pelican eel Hairy angler fish Halfmoon fish Halibut Hardyhead silversides Hatchetfish Jack mackerel Jacks Kelp bass Kelp perch Lantern fish Leafy seadragons Lingcod Lionfish Lumpsucker Mackerel icefish Malacosteus/Sniper scope fish Moray eel Ocean trigger fish Opaleye Parrotfish Pilot fish Pipefish Powder-blue tang Redfin butterflyfish Redmouth grouper Remora Sand goby Sandlance/    Sand eel Sardine Señorita Shanny/    Common blenny Skipjack tuna Sockeye salmon Striped marlin Sunfish/    Common mola Swordfish Tarpon Tripod fish Vent fish Wahoo Waving lure angler    Himantolophus/    Football fish White-spotted surgeonfish Winteria Wolfeel/    Wolffish Yellowfin goatfish Yellowfin grouper Yellowfin tuna __________________ **Cartilaginous fish** __________________ Basking shark Bat ray Blue shark Bronze whaler shark Bull shark Dogfish shark/    Spurdog Dusky shark Eagle ray Golden cownose rays Great hammerhead Great white shark Grey reef shark Horn shark Leopard shark Manta Marbled ray Oceanic whitetip Salmon shark Sand tiger Scalloped hammerhead Shortfin mako Sixgill shark Sleeper shark Stingray Tiger shark Whale shark Whitetip reef shark __________________ **Jawless fish** __________________ Hagfish/    Slime eel

Fish

All fish are aquatic and are found in fresh and salt water throughout the world. There are three main classes: the jawless fish (Agnatha), bony fishes (Osteicthyes) and cartilaginous fishes (Chondrichthyes).

The jawless fishes, such as lampreys and hagfish, are the only fish that have sucking mouthparts, which makes them dependent on a parasitic way of life. They are primitive fish and fins are either absent or poorly developed.

Bony fish possess true ossified, internal skeletons to support the body tissues and a rigid skull of fused dermal bones. Most also have external scales covering the body and a bony flap, the operculum, covering a single gill exit. The spiracle is reduced or lost in bony fishes and the majority have swim bladders evolved from the primitive fish lung. Their eyes are large and of primary sensory importance. The fins are flexible and often able to be folded against the body. This is the biggest class of fish and includes about 20,000 species.

There are around 900 species of cartilaginous fish. Sharks and rays are two examples that belong to one subclass (Elasmobranchii). These differ from bony fishes in having flexible, cartilaginous skeletons, sometimes strengthened by salt deposits.

Elasmobranchs are covered with tooth-like scales called denticles, which helps strengthen the body's structure. They have multiple, uncovered gill exits and they have a good sense of smell. They have long snouts and their jaws are set well back from the snout tip. Their teeth are replaced continually, and arranged in multiple rows. Sharks have rigid and fleshy fins that cannot be folded flat. Some species retain the spiracle behind the eyes which is used in respiration on the bottom of the sea. Swim bladders and lungs are absent and buoyancy is controlled by storing a high level of oil in the liver. Fertilisation is usually internal and females either give birth to young or produce yolky eggs.