Western Mosquitofish (Gambusia affinis) Care Guide
Gambusia affinis is a hardy North American livebearer widely introduced for mosquito control and now considered invasive in many regions.
Overview
Gambusia affinis, the western mosquitofish, is a small livebearing fish of the family Poeciliidae described by Baird & Girard in 1853. It is native to North America and has been introduced worldwide for mosquito control, though it is now regarded as an ecological pest in many regions.
Taxonomy
- Family: Poeciliidae
- Genus: Gambusia
- Scientific name: Gambusia affinis
- Author: Baird & Girard, 1853
Habitat
The native range covers the Mississippi River basin from central Indiana and Illinois south to the Gulf of Mexico, plus Gulf-slope drainages into Mexico. It inhabits standing to slow-flowing freshwater and brackish habitats, particularly vegetated ponds, lakes and stream backwaters. It is among the most widely introduced fishes globally.
Tank requirements
- Minimum tank volume: 60 L
- Temperature: 10-30 °C (50-86 °F)
- pH: 6.5-8.5
- GH: 8-25 °dGH
- Lifespan: 2-3 years
- Tolerant of wide temperature and salinity ranges
Diet
The species is an omnivorous surface predator feeding on zooplankton, small insects and detritus. Mosquito larvae form only a small portion of its natural diet, although adult females can consume large numbers daily. In the aquarium it accepts a wide range of foods.
Compatibility
It is a semi-aggressive, top-swimming fish prone to fin-nipping. It is best kept in a single-species setup; long-finned fish should be avoided.
Breeding
Gambusia affinis is viviparous, with internal fertilization via a modified anal fin (gonopodium). Females carry about 30 young and gestation lasts roughly 24 days to a month. Breeding is easy and prolific.
Conservation status
IUCN Red List: Least Concern (assessed 2019). FishBase classifies it as a potential pest; it competes with native fishes and can disrupt local ecological balance, and several jurisdictions restrict its import or release.