Blue crayfish is the same species as normal colored crayfish. Sometimes they are called lobsters as well, because everybody knows what lobster is and crayfish is something unknown, but it in not the same. Lobsters have two claws where each is of different size, but crayfish have claws of the same size. The blue color is caused by gene mutation just like albino form of any animal or human species. However, just like other artificial color mutations, this blue color causes that an animal with blue color is eaten very quickly.