Gambusia

Gambusia is a large genus of fish in family Poeciliidae (order Cyprinodontiformes). Gambusia contains over 40 species, most of which are principally found in freshwater habitats, though some species may also be found in brackish or saltwater habitats. The type species is the Cuban gambusia, G. punctata. The greatest species richness is in Mexico, Texas, and the Greater Antilles, but species are also found elsewhere in eastern and southern United States, The Bahamas, Central America, and Colombia. Gambusia species are often called topminnows or simply gambusias; they are also known as mosquitofish, which, however, refers more specifically to two species, G. affinis and G. holbrooki. These can be introduced into ponds to eat mosquito larvae. As a consequence, they have been introduced widely outside their native range, and sometimes become invasive, threatening the local species. They are very important in aquarium trade, desired for small size, ease of breeding, and charming gracefulness. They are viviparous—they have live young.