Gambusia is a large genus of viviparous fish in the family Poeciliidae. The type species is the Cuban gambusia, G. punctata.
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.
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 frequently become invasive, threatening the local species. They are only occasionally kept in aquariums, due to their relative lack of colour and the highly aggressive nature of the aforementioned mosquitofish species.
- Gambusia affinis
- Gambusia alvarezi
- †Gambusia amistadensis
- Gambusia atrora
- Gambusia aurata
- Gambusia baracoana
- Gambusia beebei
- Gambusia bucheri
- Gambusia clarkhubbsi
- Gambusia dominicensis
- Gambusia echeagarayi
- Gambusia eurystoma
- Gambusia gaigei C. L. Hubbs, 1929
- Gambusia geiseri
- †Gambusia georgei
- Gambusia heterochir
- Gambusia hispaniolae
- Gambusia holbrooki
- Gambusia hurtadoi
- Gambusia krumholzi
- Gambusia lemaitrei
- Gambusia longispinis
- Gambusia luma
- Gambusia manni
- Gambusia marshi
- Gambusia melapleura
- Gambusia monticola
- Gambusia myersi
- Gambusia nicaraguensis
- Gambusia nobilis
- Gambusia panuco
- Gambusia pseudopunctata
- Gambusia punctata
- Gambusia puncticulata
- Gambusia quadruncus
- Gambusia regani
- Gambusia rhizophorae
- Gambusia senilis
- Gambusia sexradiata
- Gambusia speciosa
- Gambusia vittata
- Gambusia wrayi
- Gambusia xanthosoma
- Gambusia yucatana
- Gambusia zarskei