Native to North and Central America, the mosquitofish isn’t exactly the belle of the aquatic ball. A plain relative of the guppy, the mosquitofish has little use for the indoor aquarist other than as live food for larger, more interesting tank residents.
Outside, however, the mosquitofish is an essential resident of pools and water features. The voracious little fish targets and eats pesky aquatic insect larvae before they mature, including the mosquito (hence the name).
Mosquitoes and North America
Mosquitoes are usually thought of as an annoying summertime pest, but the little bloodsuckers are capable of transmitting virulent diseases. North American mosquitoes have long carried St. Louis encephalitis, western equine encephalitis and eastern equine encephalitis.
With climate changes and invasive mosquito populations, the United States is seeing an increase in mosquito-borne disease. West Nile Virus is now well-established on the continent. Texas now sees outbreaks of Dengue fever, a disease also found in Hawaii. Controlling mosquitoes is no longer just about avoiding itchy bites; now it’s about health and well-being.
Outdoor Ponds and Mosquitofish
The need for mosquito control brings us back to the mosquitofish, which may qualify as nature’s best mosquito trap. Like guppies, mosquitofish are live breeders. A brood can include as many as 100 quarter-inch fry, all of which are capable of eating mosquito larvae from birth.
Mosquitofish are used to control insects in outdoor pools, unused swimming pools and even animal drinking troughs. The 3-inch adults are hardy little fish, but they’re peaceful enough to be kept with other pond fish. In addition to mosquito larvae, they eat other water-based insect larvae and help control algae.
Physically, the mosquitofish isn’t much to look at. Males are smaller than females, with narrow bodies and a pointed anal fin. Females are larger, with deeper bodies and a rounded anal fin. Both sexes are a plain grayish-white in both the body and the tail.
If you choose to add mosquitofish to your pond, give them some vegetation to hide in. Fry benefit from floating plants or a breeding patch, as adults will cannibalize fry unless you provide newborns a safe hiding place. If the pond doesn’t produce enough wild food, you can feed mosquitofish with a standard flake food.
In colder climates, mosquitofish are capable of surviving winter in the pond, assuming the pond doesn’t freeze to the bottom. Aerating the water during winter helps the fish survive.
Like any aquarium or pond fish, mosquitofish should not be released into the wild, where they can damage local ecosystems. In California, for instance, released mosquitofish have been linked to declines in several amphibian species.
When used as mosquito control in home ponds, however, the mosquitofish is a highly effective pest controller.
Adrienne Erin is a prolific writer who loves animals, writing, and speaking French. Catch up with her recent projects by following her on Twitter: @adrienneerin
Image credit: Wikipedia