Gambusia Affinis | Print |

The Gambusia affinis, more commonly known as the 'Western Mosquito Fish', is a very important part of the district's control efforts (IPM - Integrated Pest Management).

Every Season (~May, 2017), CDVCD supplies the Columbia County community with FREE Mosquito fish, so everyone can help keep mosquito populations down, especially in their own neighborhoods.

We will post on the website when the breeding ponds are set up and we start giving them away. When the program is set up and ready to go, feel free to stop by the building in St. Helens with a small container, like a coffee can, or small bucket. We'll have a couple available if needed.


If you want your gambusia to breed in your designated enclosed habitat, please ensure you have males and females both. Females are distinct with a black spot on the posterior of their abdomen, and males are a bit smaller. (16 - 28 day gestation period = ~ 60 young).

*Don't worry, here at CDVCD, we'll do the work for you if you need! That's our job.

This small freshwater fish may be placed in any ornamental pond or watering trough to control populations of mosquitoes (~8 - 12 fish per). For larger bodies of water, more gambusia will be needed for control, and some gambusia have the ability to winter-over in deeper ponds. These fish also feed on zooplankton, beetles, mayflies, mites, and other invertebrates, making mosquitoes only a portion of their diet.





*Important note:

Gambusia were initially introduced as a control for locations with high mosquito populations. Unfortunately, gambusia can be quite detrimental to other fish and amphibian ecosystems. Please use gambusia fish as they were intended and keep them away from open water sources and main waterways. gambusia must stay in enclosed systems like ornamental ponds, and watering troughs please.



USGS Nonindigenous Aquatic Species - Gambusia affinis