Crayfish are freshwater crustaceans that are related to lobsters. During the day they spend most of their time at the bottom of streams, rivers, lakes, etc hiding under the rocks and logs. At night they come out to feed on minnows, tadpoles, fish eggs, insect larva, worms, snails and algae. There are three different families of crayfish consisting of over five hundred species. Members from two of the families can be found in North America, Atacidae, which is found in the west as well as in Europe and western Asia, and Cambaridae, which can be found in eastern North America and eastern Asia. The other family Parastacidae are found in several places in the southern hemisphere such as South America, south Asia and Australia.