There are about 25,000species (kinds)of fishes.Fish come in all sizes.The huge whale shark can be 40feet (12meters)long.The tiny goby is only 0.4inch (1centimeter)long.
Most fish are called jawed fish.Hagfish and lampreys are jawless fish.They are more like eels.Eels are fish that look like snakes.Jawless fish do not have fins,scales,or jaws with teeth.
All other fish have jaws.There are bony jawed fish and cartilaginous jawed fish.Bony fish have skeletons made of bone.Cartilaginous fish have a softer material called cartilage instead of bone.Sharks,rays,and chimaeras are cartilaginous fish.
How Fish Swim
