Mosquitofish or Gambusia affinis is a tiny silver-colored fish. It is a freshwater species belonging to family Poeciliidae and order Cyprinodontiformes. The name is derived from a Cuban Spanish term gambusino which means useless. Even though its name means useless, this tiny fish has proved its utility. These tiny fish feed on larvae of insects and their primary source of food is mosquito larva. Mosquitoes lay their eggs in ponds which grow into larvae and become a great source of diet for mosquitofish. They also feed on algae, thus helping in maintaining a balance in the pond's ecosystem. In case, natural resource of food is not available, a good quality flaked fish food can be used to feed them.