How to Use Mosquitofish to Control Mosquitoes

Mosquitoes need water to breed, which is why if you have any water in your backyard you might have noticed an increase in mosquitoes. Mosquitoes do have a natural predator here in the United States that you can use to your advantage-the Mosquitofish (also spelled mosquito fish). Using the mosquitofish to control mosquitoes is not new; it has been done for over eighty years.

Mosquitofish, or Gambusia affinis, look similar to a female guppy and is about one- to three-inches long. They are native to southern and eastern United States, but have been making their way across the country as they become more popular. They are very hardy and will adapt to a variety of different temperatures and water types. Although they prefer the warmer climates, a few varieties have been bred that are capable of surviving the colder climates, even down to -30ºF.

Mosquitofish get their name because they happen to love the larvae of mosquitoes. They have voracious appetites and been known to attack the larvae when they are only a couple of hours old. One mosquito fish is capable of eating anywhere from 100-200 mosquito larvae a day.

Mosquitofish are livebearers, meaning they do not lay eggs. They can produce three or four broods each summer. Broods are born about six weeks apart and will consist of between fifty to one hundred young. Young will become sexually active with they are six to eight weeks old. Overpopulation is not a problem, however, because the mosquitofish are also aggressive towards each other. Mosquitofish live about two-to-three years

Mosquitofish should not be used in every water feature. Unfortunately, they are not only aggressive towards mosquitoes, but also dragonfly larvae, tadpoles, and other fish. They should not be introduced into a natural lake, stream, river, or creek because they could disrupt the natural balance there. If you need to control mosquitoes in ornamental ponds that already have fish, consider adding goldfish or guppies. If you need to eliminate mosquito larvae in natural water features, regular minnows are your best bet.

Mosquitofish are perfect for any water feature that does not already have its own inhabitants such as ornamental ponds, birdbaths, unused or "out-of-order" swimming pools (providing they are not chlorinated), and animal water troughs. If you have a large birdbath that is constantly filled with water, you will need to add about ten fish. Larger ornamental ponds can support anywhere from thirty-five to one hundred fish.

Mosquitofish are easy to find since they are often given away free by local governmental agencies in an attempt to control mosquitoes. You might also find them at your local nursery or greenhouse, and there are several sites on the internet that sell them.

Controlling mosquitoes is necessary, not simply for your own comfort but for your health. Finding ways that won't add toxic chemicals, such as the mosquitofish, is a great and inexpensive way to do it.