Fish

 are Animals with scales and fins that live underwater. They have gills that help them breath, instead of lungs. They reproduce by laying eggs. Sharks, eels, flounders, goldfish, and catfish are all Fish.

Facts

 * The largest Fish is the Whale Shark. Despite its name, it is actually a shark, and not a whale, which is a Mammal.
 * Scientists believe that Amphibians evolved from Fish.
 * Fish eggs lack a shell, like Amphibian eggs.