Mosquitofish

The western mosquitofish (Gambusia affinis) is a species of freshwater fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, gambusia, or by the common name gambezi. There is also an eastern mosquitofish (G. holbrooki).

Mosquitofish are small in comparison to other fish, with females reaching an overall length of 7 centimeters (2.8 in) and males at a length of 4 centimeters (1.6 in). Females can be distinguished from males by their size and a gravid spot at the posterior of their abdomen. The name "mosquitofish" was given because the diet of this fish predominantly 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.

Mosquitofish were introduced directly into ecosystems in many parts of the world as a biocontrol to lower mosquito populations which in turn negatively affected many other species in each distinct bioregion.

Fertilization is internal, the male secreting milt into the genital aperture of the female through his gonopodium. Within 16 to 28 days after mating, the female will give birth to about 60 young. 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 in six to seven months.

Read more about Mosquitofish:  Description, Naming and Taxonomy, Diet, Habitat, Environmental Impact, Reproduction, Embryology, Growth