The name "mosquitofish" was given because the diet of this fish sometimes consists of large amounts of mosquito larvae, relative to body size. Several counties in California distribute mosquito fish at no charge to residents with man-made fishponds and pools as part of their Mosquito Abatement programs. The fish are made available to residents only and are to be used only on their own property, not introduced into natural habitat.
Fun Fact Mosquitofish in Australia are classified as a noxious pest and may have worsened the mosquito problem in many areas by outcompeting native invertebrate predators of mosquito larvae.