Mosquitofish

Mosquitofish (Gambusia affinis) are small (1-2 inch) freshwater fish that provide an effective and natural method of mosquito control. Young mosquitoes (larvae) live in standing water. Mosquitofish can eat hundreds of mosquito larvae each day. By eating mosquito larvae, mosquitofish help prevent mosquito bites and mosquito-borne illnesses.

Mosquitofish are ideal for artificial bodies of water such as: backyard ponds, birdbaths, fountains, animal troughs, unused swimming pools, etc.

 

No Mosquitofish in Natural Waterways

Mosquitofish should never be placed in a natural habitat such as lakes, streams, rivers, or creeks as they may compete with native species. 

Find the nearest mosquitofish distribution location


Mosquito Larvae

 

Female mosquitoes lay their eggs in standing water sources. The eggs hatchi into larvae that grow into biting adult mosquitoes in 7 days or less. 

Adult female mosquitoes bite humans and animals and can spread diseases such as West Nile virus, Zika, Dengue, and yellow fever. Controlling mosquito larvae limits the number of adult mosquitoes and lessens the chance of getting bit by mosquitoes that spread diseases.

 

 


Caring For Mosquitofish

 

Let your mosquitofish get used to their new home. Keep them in their container and place it directly into the pond for 15 minutes. Wait until the pond and the container's water reach the same temperature. Then release the fish into the pond. After that, mosquitofish need little to no care.

Keep chlorine, garden insect sprays, and yard chemicals out of their water. 

 

During warm months mosquito fish usually do not need to be fed. For small sources with less than 20 fish, feed regular fish flake food during the winter if no mosquito larvae are present.

Mosquitofish are compatible with most ornamental pond fish of about the same size. If the mosquitofish are living with larger fish (who may eat them), they need hiding places like rocks and vegetation.

Mosquitofish give birth to live young, rather than laying eggs. Fish live for about 1 year and start eating mosquito larvae at birth. Mosquitofish do not overbreed and maintain population levels that fit their environment.


How Many Fish do I Need?

  • Small sources (such as fountains or troughs): 2-3 fish
  • Ponds (surface area less than 200 square feet): 3-5 fish
  • Larger sources: 1 fish for every 20 square feet of surface area (up to 100 fish to start, as they will breed to fill the source)

Where Do I Get Mosquitofish?

  • Contact us to setup an initial distribution of up to 100 fish.
  • Need fewer than 5 mosquitofish? They can be picked up free of charge at over 10 locations throughout San Diego County, including our office: 5570 Overland Ave. Suite 102, San Diego, CA 92123

Return to the prevention page


Questions?

  (858) 694-2888

  vector@sdcounty.ca.gov