An ordinary goldfish eats mosquito larvae, decimating the flying, biting, disease-carrying pests. Mosquitoes use standing water to breed, so ponds, fountains, rain barrels and water gardens can become pest nurseries. Mosquitoes go beyond being a nuisance, they may transmit serious diseases, including the West Nile virus. The job of eating mosquitoes doesn't require a certain type of goldfish, although smaller ones have an advantage.
Aerating your pond or other water feature helps to keep it clear of mosquito larvae. Mosquitoes seek standing water, preferring stagnant conditions. Water that stays fresh and in motion with a pump system doesn't attract them as a breeding ground. To save energy, consider using a solar pump. In addition to goldfish, mosquito fish, minnows, koi and guppies eat mosquito larvae.
Certain dark-colored goldfish may have a survival advantage in exposed ponds. Their less-visible coloring may allow them to evade some predators. Shubunkin or comet goldfish are dark on top and blend into their surroundings better than pale or brightly colored goldfish. You can increase their chance of survival by keeping the pond free of ledges and islands that predators can use as places to stand while fishing.
Larger fish may be impeded from reaching mosquito larvae, so when it comes to keeping your pond mosquito-free, opt for small goldfish. The smaller fish swim through water garden plants and maneuver easily to reach all areas of their environment, so they can do a more complete job of getting rid of mosquitoes. A deep pool provides a safer environment for your mosquito-eating goldfish than a shallow pool. Raccoons and other fish-loving predators catch fish more easily in shallow water.
Pond and Water Garden Issues
Goldfish also control algae, keeping your water features free of messy green overgrowth. Goldfish may chow down on water plants, yet they provide beneficial fertilizer for plants via their waste. Water lilies generally withstand their nibbling and add shade for the goldfish. Raccoons go for goldfish the way goldfish go for mosquito larvae. To avoid adding goldfish sushi to your local raccoons' menu, the National Gardening Association suggests opting for mosquito fish instead of goldfish.
Gryphon Adams began publishing in 1985. He contributed to the "San Francisco Chronicle" and "Dark Voices." Adams writes about a variety of topics, including teaching, floral design, landscaping and home furnishings. Adams is a certified health educator and a massage practitioner. He received his Master of Fine Arts at San Francisco State University.