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Photo of a Western Mosquitofish

Species profile

Western Mosquitofish

Gambusia affinis

Bony fishIUCN: Least Concern18.8K iNat observations

Identify Western Mosquitofish (Gambusia affinis) from a photo — free, unlimited, no sign-up — with the CatchRules iPhone app. Plus current fishing rules across 2 jurisdictions.

At a glance

Western Mosquitofish (Gambusia affinis) is an IUCN Least Concern bony-fish species regulated in 3 of 66 jurisdictions tracked by CatchRules across the U.S. and Canada.

Confirmed by 14,850 research-grade iNaturalist observations, with Texas, California, and Ohio the top jurisdictions by observation count.

Notable details

  • Females grow up to 7 cm; males are much smaller, rarely exceeding 3.5 cm.
  • Gives birth to live young rather than laying eggs, producing several broods per year.
  • A single fish can consume up to 100 mosquito larvae per day.
  • Tolerates water temperatures from near freezing to 42°C and survives in low-oxygen conditions.
  • Introduced to over 40 countries for mosquito control, it is now considered invasive in many regions.

Background

The western mosquitofish (Gambusia affinis) is a species of freshwater fish, also known commonly, if ambiguously, as simply mosquitofish or by its generic name, Gambusia, or by the common name gambezi. There is also an eastern mosquitofish (G. holbrooki).

Background excerpt adapted from Wikipedia's Western Mosquitofish article (CC BY-SA). Visit Wikipedia for the full entry.

Frequently asked questions

What is Western Mosquitofish?

Western Mosquitofish (Gambusia affinis) is an IUCN Least Concern bony-fish species regulated in 3 of 66 jurisdictions tracked by CatchRules across the U.S. and Canada.

What is the scientific name for Western Mosquitofish?

Western Mosquitofish is Gambusia affinis.

Is Western Mosquitofish regulated for fishing?

Yes — Western Mosquitofish has fishing regulations in 2 U.S. states and/or Canadian provinces tracked by CatchRules. See the "Jurisdictions with rules" section above for the binding-source links.

How can I identify Western Mosquitofish?

Take a photo with the free CatchRules iPhone app — on-device identification recognizes Western Mosquitofish along with ~1,500 other species. No sign-up, unlimited use.

Photo credit: iNaturalist / Wikipedia. Identification reference only — verify regulations with the issuing wildlife agency before retaining a catch.