HomeFreshwater aquarium fishGuppies & livebearersMosquitofish Mosquitofish (Gambusia affinis) Scientific name: Gambusia affinis Baird & Girard, 1853 The Mosquitofish (Gambusia affinis) is a freshwater fish of the family Poeciliidae that grows to about 4 cm (1.6 in). It is easy to keep and semi-aggressive, suits community aquariums and needs a tank of at least 40 L (11 US gal), water at 12–29°C (54–84°F) and a pH of 6.0–8.0. Native range: North and Central America, United States North to central Indiana and Illinois and Gulf Slope drainages west to Mexico. Mosquitofish care at a glanceCare levelEasyTemperamentSemi-aggressiveCommunity tankGoodAdult size4 cm (1.6 in)Minimum tank40 L (11 US gal)Temperature12–29°C (54–84°F)pH6.0–8.0Hardness5–19 dGH (89–339 ppm)DietOmnivore. Accepts flakes, wafers, frozen foods and live foods. BiologyDorsal spines (total): 0; Dorsal soft rays (total): 7-9; Anal spines: 0; Anal soft rays: 9 - 10. Origin of dorsal fin opposite 7th anal ray. Length of anal base much less than half distance from caudal. 8 horizontal scale rows between back and abdomen. Ventrals terminate immediately before anal fin. Pelvic fins reach ventrals.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameGambusia affinisFamilyPoeciliidae (Poeciliids)OrderCyprinodontiformes (Live bearers, Killifishes and Rivulines)ClassActinopterygii (Ray-finned fishes)Maximum length4.0Common length3.9EnvironmentFreshwater; brackish;; pH range: 6.0 - 8.0; dH range: 5 - 19 benthopelagic; potamodromousClimateSubtropicalDistributionNorth and Central America: Mississippi River basin from central Indiana and Illinois in USA south to Gulf of Mexico and Gulf Slope drainages west to Mexico. One of the species with the widest range of introductions which acquired for itself a near pan-global distribution. Several countries report adverse ecological impact after introduction.Conservation status (IUCN)Not EvaluatedThreat to humansPotential pestUsesFisheries: minor commercial; aquarium: commercialResilienceMedium, minimum population doubling time 1.4 - 4.4 years (K=1.20; tmax=3; Fec=10-60) More guppies & livebearersSailfin mollyPoecilia latipinnaGuppyPoecilia reticulataGreen swordtailXiphophorus helleriiSouthern platyfishXiphophorus maculatusMollyPoecilia sphenopsBlackbarred limiaLimia nigrofasciataSee all guppies & livebearers Can it live with...?Mosquitofish and Black ghostMosquitofish and Black sharkminnowMosquitofish and Blackbarred limiaMosquitofish and Bleeding-heart tetraMosquitofish and Bloodfin tetraMosquitofish and Bluespotted corydorasMosquitofish and Bluetail goodeaMosquitofish and Bold characodonMosquitofish and Brilliant rasboraMosquitofish and Butterfly splitfinMosquitofish and Chinese suckerMosquitofish and Clown barbMosquitofish and Clown loachMosquitofish and Clown rasboraMosquitofish and Crescent bettaMosquitofish and Dwarf botiaMosquitofish and Dwarf rainbowfishMosquitofish and Eel LoachMosquitofish and Forktail rainbowfishMosquitofish and Gangetic leaffishMosquitofish and Garnet tetraMosquitofish and Glass catfishMosquitofish and Glowlight tetraMosquitofish and Goldeneye cichlidMosquitofish and Gulf gambusiaMosquitofish and Head-and-taillight tetraMosquitofish and Horseface loachMosquitofish and Indian glassy fishMosquitofish and Lake Kutubu rainbowfishMosquitofish and Lampeye panchax SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0. Aquarium care parameters compiled, checked and converted to metric and imperial units by Guppies.za.net.Last updated 28 September 2026