---
title: "Western Mosquitofish"
description: "Gambusia affinis — Fish. The western mosquitofish (Gambusia affinis) is a North American freshwater poeciliid fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, Gambusia, or by the common name gambezi."
canonical: https://animalchecklist.com/animal/western-mosquitofish
last_updated: 2026-09-20
---

# Western Mosquitofish

> Gambusia affinis — Fish. The western mosquitofish  (Gambusia affinis) is a North American freshwater poeciliid fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, Gambusia, or by the common name gambezi.

- Scientific name: *Gambusia affinis*
- Category: `fish` (Fish)
- Habitats: `freshwater` (Lakes & rivers)
- iNaturalist observations: 21641
- Wikidata: [Q723904](https://www.wikidata.org/wiki/Q723904)
- iNaturalist taxon: [59115](https://www.inaturalist.org/taxa/59115)

## Names

- en: Western Mosquitofish
- de: Koboldkärpfling
- es: Guayacón mosquito
- fr: Gambusie de l’Ouest
- pl: Gambuzja pospolita

## Countries with the most observations

US (17503), TW (624), MX (334), CN (294), NZ (283), JP (133), CA (132), ZA (130), HK (112), SG (70), TH (65), ID (56)

## Summary

The western mosquitofish  (Gambusia affinis) is a North American freshwater poeciliid fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, Gambusia, or by the common name gambezi. Its sister species, the eastern mosquitofish (Gambusia holbrooki) is also referred to by these names.
Mosquitofish are small in comparison to many other freshwater fish, with females reaching a maximum length of 7 cm (2.8 in) and males a maximum length of 4 cm (1.6 in). The female can be distinguished from the male by her larger size and a gravid spot at the posterior of her abdomen. The name "mosquitofish…

Text: Wikipedia (en), CC BY-SA 4.0 — https://en.wikipedia.org/wiki/Mosquitofish

## Photo

![Western Mosquitofish](https://animalchecklist.com/img/animals/western-mosquitofish/medium.jpg)

Photo: August Frisk · CC0 · inaturalist — https://www.inaturalist.org/observations/143997585

## Machine access

`GET https://animalchecklist.com/api/v1/animals/western-mosquitofish?lang=en` — see [openapi.json](https://animalchecklist.com/openapi.json).