What are those things?

Crossing the spillway along York River State Park's Woodstock Pond, it's not unusual to see tiny fish swimming in the shallows. Are they minnows? Baby bass? Maybe they are tadpoles? No, they are mosquito fish (Gambusia holbrooki). Unlike most fish, Gambusias don't lay eggs, but bear their young alive.  

Pest Control

Mosquito fish are native to eastern Virginia, going south to Florida and the Caribbean area. Their name is a clue to their diet. This fish feeds heavily on mosquito eggs and larvae. Freshwater ponds and slower-moving creeks with a significant population of mosquito fish are less likely to have problems with the pest. This trait has encouraged private and public pond managers to introduce these fish outside of their native range, even in our state. However, they can bully and out populate native minnow species that also feed on insect larvae. The reduction in biodiversity can cause unintended problems. So, it's best to return creatures to where they have been captured.

Catching Mosquito Fish

Finding and viewing mosquito fish is a highlight of our popular Stream to Sea ranger-guided programs. They can be seen schooling along the concrete portion of the spillway almost year-round. They are often spotted from the docks and anywhere near the shoreline. Long-handled dip nets are effective in catching medium and larger specimens. Shorter, fine-meshed nets are only useful right at the pond bank. Some days, our Dabble in Discovery program will feature a ranger with a few mosquito fish and other creatures. Check our calendar of events for these and other events. Groups of 10 people or more can call our interpretive staff at 757-566-8523 to reserve a ranger-guided experience.  

Homely Guppies

Park guests are not allowed to take mosquito fish home as pets. However, anyone can experience having more attractive relative species in an aquarium. The Gambusia family includes guppies, mollies, platties, swordtails and other live-bearing fish that can be found in most pet stores. In comparison, the pet fish have a greater variety of colors and interesting fin shapes. After viewing them, return the "Plain Jane Guppies" back to the pond to keep the mosquito population down. This helps us all have a great day at the park.

Learn more about York River State Park.