PLEASE NOTE: In-person fish pick up is not available. Contra Costa County residents may request mosquitofish from the District online or by calling 925-685-9301.

Upon receiving your request for mosquitofish, a District employee will follow up with you and make an appointment for an inspection. During the inspection, the District employee will determine if the water feature is an appropriate location for the fish. If the location is appropriate for mosquitofish, the District employee will place fish in the water feature. If, for example, the water feature is found to be producing more mosquito larvae than the fish can initially handle, the District employee will provide assistance and advice on the appropriate action to mitigate the mosquito issue.

Mosquitofish may be used in ornamental ponds, horse troughs, stock ponds and other artificial water bodies and may not be placed by the public in creeks or natural water sources.

By law, only vector control technicians can place fish in water sources other than those located on private property. Some common 'sources' or sites where these fish are stocked include; artificial lakes, irrigation ditches, storm channels, and natural industrial ponds. Of course, we encourage residents to get free fish from our District to take home and place in their own backyard pond, horse trough, or neglected swimming pool.

To avoid competition with sensitive native amphibian and fish species, we do not stock mosquitofish in habitats where such species are known to be present.