Species: G. affinis
Maximum Size: 1.5” (males), 3” (females)
Temperature: 65-74 F
Hardness: 10-30 dH
Brackish Tolerance: 1.000-1.025
Minimum Tank Size: 15 gallons
Feeding: Flake foods accepted, does best on brine shrimp, Mysis shrimp, insect larvae
Notes: Mosquitofish are not commonly found in the aquarium trade, though are sometimes inadvertently sold in batches of wild-type and feeder guppies. Mosquitofish are remarkably adaptable and have been shown to tolerate temperatures up to 108 F and specific gravities up to twice sea water for short periods of time. Long term, they are best kept in cold-to-subtropical conditions with hard water. They are good candidates for outdoor ponds that are too small for groups of goldfish.
In the home aquarium, they are extremely aggressive, nippy fish that often do not tolerate any other fish in their territory. Gobies, Hoplosternum catfish, and some of the more aggressive crabs like Red Clawed Crabs are possible tankmates, but may not be suitable long term. Species-only aquariums are better choices and even then multiple males will likely fight in any moderately sized tank.
Like other fish in the Poecilidae family, they produce live young at regular intervals (about every 3-4 weeks). No special steps need to be taken by the aquarist to trigger spawning, but fry should be moved to another tank if wanted to be kept alive.
FAQs on the Gambusia, Heterandria spp. Mosquitofish, Wetwebmedia
Gambusia affinis (Western Mosquitofish), Seriously Fish
issg Database: Ecology of Gambusia affinis, Global Invasive Species Database
Campton, D. E.; Gall, G. A. E. (1988). “Growth and reproduction of the mosquitofish, Gambusia affinis, in relation to temperature and ration level: consequences for life history”. Environmental Biology of Fishes