We all have seen fish. They are very elegant in their colors, and many people love to keep fish as pets. Fish can be defined as aquatic vertebrate animal whose body may or may not be covered with scales and carries two sets of paired fins and a lot of the unpaired fins.
Fish are cold-blooded, or ectothermic animals, which means that their body temperature continues to change with the water temperature. Fish are divided in all aquatic habitats ranging from mountain streams to the deepest oceans.
About 32,500 species are known, and together they form the greatest variety of organisms, as compared with other classes of vertebrates. Fish are also caught by the fish keepers and are kept in aquariums as a decoration source. They are also associated with films, cultures and religions.
Fish images gallery