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How mosquitofish can help protect you from mosquitoes

Mosquitofish (Gambusia affinis) were first introduced into California for the control of mosquito larvae in the 1920’s and continue to be an important biological control measure to this day. These fish are routinely used by our vector control technicians to control mosquito larvae in backyard water sources, water troughs, neglected swimming pools and other artificial containers that are at least 18 inches deep. To avoid competition with sensitive native amphibians and fish species, we do not place mosquitofish in areas where these species are known to be present.

Mosquitofish can eat up to three times their body weight in mosquito larvae each day. This means that just one adult mosquitofish could eat up to five hundred larvae per day! If that isn’t impressive enough, mosquitofish are extremely prolific and can tolerate a wide range of temperatures.

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During the winter months these fish move to the bottom of their habitat, become inactive, and do not feed. In most cases they will survive the winter and become active again in the spring when the temperatures rise.

Mosquitofish generally do not need supplemental food, as established ponds will naturally supply them with their daily diet. However, when placing mosquitofish in newly constructed or recently cleaned water features where natural food is absent, supplemental feeding (i.e., fish flakes, crackers, stale bread, or crumbled dog food) is necessary.

For more information about mosquitofish click here.


How to obtain mosquitofish:

Come to our office: We have a self-service station set up in front of our office at 595 Helman Lane, Cotati (Monday-Friday 7 AM - 3:30 PM). No need to bring a container; we provide them for you.

Request delivery: We offer free delivery of mosquitofish. There is no need to be home; one of our vector control technicians will place mosquitofish in your pond or water feature and leave a note on your door. To request delivery please call our office at 707-285-2200 or place a service request online at

Please note that it is against California Department of Fish & Game regulations for private citizens to plant mosquitofish in waters of the state without a permit (Title 14 CCR, Fish and Game Code, Section 1.63, Section 6400, and Section 238.5). Therefore, we ask that you do not place mosquitofish into areas that may overflow into U.S. waterways (creeks, vernal pools, streams, rivers, stormwater systems, etc.)

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