Mosquitofish

Mosquitofish
Female
Male
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cyprinodontiformes
Family:	Poeciliidae
Genus:	Gambusia
Species:	G. affinis
Binomial name
Gambusia affinis (S. F. Baird & Girard, 1853)
Synonyms[2]
Heterandria affinis S.F Baird & Girard, 1853 Heterandria patruelis S.F. Baird & Girard, 1853 Gambusia patruelis (S.F. Baird & Girard, 1853) Zygonectes patruelis (S.F. Baird & Girard, 1853) Gambusia gracilis Girard, 1859 Zygonectes gracilis (Girard, 1859) Gambusia humilis Günther, 1866 Haplochilus melanops Cope, 1870 Zygonectes brachypterus Cope, 1880 Zygonectes inurus D.S. Jordan & Gilbert, 1882 Fundulus inurus (D.S. Jordan & Gilbert, 1882)

The western mosquitofish (Gambusia affinis) is a North American freshwater poeciliid fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, Gambusia, or by the common name gambezi. Its sister species, the eastern mosquitofish (Gambusia holbrooki) is also referred to by these names.

Mosquitofish are small in comparison to many other freshwater fish, with females reaching a maximum length of 7 cm (2.8 in) and males a maximum length of 4 cm (1.6 in). The female can be distinguished from the male by her larger size and a gravid spot at the posterior of her abdomen. The name "mosquitofish" was given because the fish eats mosquito larvae, and has been used more than any other fishes for the biological control of mosquitoes.^[3] Gambusia typically eat zooplankton, beetles, mayflies, caddisflies, mites, and other invertebrates; mosquito larvae make up only a small portion of their diet.^[4]

Mosquitofish were introduced directly into ecosystems in many parts of the world as a biocontrol^[5] to lower mosquito populations which in turn negatively affected many other species in each distinct bioregion.^[6] Mosquitofish in Australia are classified as a noxious pest and may have exacerbated the mosquito problem in many areas by outcompeting native invertebrate predators of mosquito larvae. Several counties in California distribute mosquitofish at no charge to residents with human-made fish ponds and pools as part of their mosquito abatement programs.^[7][8][9] The fish are made available to residents only and are intended to be used solely on their own property, not introduced into natural habitat. On 24 February 2014, Chennai Corporation in India introduced western mosquitofish in 660 ponds to control the mosquito population in freshwater bodies.^[10]

Fertilization is internal; the male secretes milt into the genital aperture of the female through his gonopodium.^[3][11] Within 16 to 28 days after mating, the female gives birth to about 60 young.^[3][12] The males reach sexual maturity within 43 to 62 days. The females, if born early in the reproductive season, reach sexual maturity within 21 to 28 days; females born later in the season reach sexual maturity the next season, in six to seven months.^[13]