Fish
Fish are animals that live and swim in the water. They have several defining characteristics, including having fins in place of limbs, are cold-blooded, have backbones, use gills for respiration, and usually have scaly skin. There are a few exceptions to some of these features, but they are generally consistant across most species.
There are over 32,000 known species of fish, which is more than all amphibians, reptiles, birds, and mammals combined.
There are over 32,000 known species of fish, which is more than all amphibians, reptiles, birds, and mammals combined.
Updated: December 4, 2014