HomeFish encyclopediaRay-finned fishesLive bearers, Killifishes and RivulinesPoeciliidsLargespring gambusia Largespring gambusia (Gambusia geiseri) Scientific name: Gambusia geiseri Hubbs & Hubbs, 1957 The Largespring gambusia (Gambusia geiseri) is a freshwater fish of the family Poeciliidae. Native range: North America, San Marcos and Guadalupe River systems in Texas, USA. Species factsScientific nameGambusia geiseriFamilyPoeciliidae (Poeciliids)OrderCyprinodontiformes (Live bearers, Killifishes and Rivulines)ClassActinopterygii (Ray-finned fishes)Maximum length4.4Common length2.5EnvironmentFreshwater; benthopelagic; non-migratoryClimateSubtropicalDistributionNorth America: San Marcos and Guadalupe River systems in Texas, USA.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026