Mosquito-eating Fish Another Weapon In Mosquito War

Last weekend (May 2003) we bought fish to add to our new pond. For now, we have mostly goldfish, except for one mosquito fish. We might add a koi later.

My new pond is quite large and when done will have a complete aquatic ecosystem of plants, water, and fish. It also has a small waterfall in one corner. The movement from the waterfall should be enough to keep mama mosquito from laying her eggs there, but if she does the fish will eat them!

 

Fish are excellent weapons in the fight against mosquitoes. The artillery includes minnows, goldfish and Gambusia affinis, also known as "mosquito fish.”  One small mosquito fish can eat up to 100 mosquito larvae each day.  They can make a big difference in a home’s water garden or small pond.

 

Mosquitoes go through their larval stage in water, whether it is a lake, river, water garden, gutter or birdbath.  Any container that holds water, and especially water that stagnates, is a prime breeding ground for mosquitoes.

 

Gambusia are related to and look very much like guppies. The males are cigar-shaped and are about an inch long. Female Gambusia are slightly larger and typically have a potbelly where they carry their developing young.  Gambusia are aggressive, eating young game and other fish.  They should not be released where they can escape into natural bodies of water. Introducing these fish to a new area carries some risk of introducing new diseases to existing fish.

 

Gambusia aren’t the only fish that eat mosquitoes.  Other surface feeding fish such as goldfish and minnows work well in controlling mosquito larva.  Koi, which tend to be bottom feeders, are not effective in controlling mosquito larva.

 

But none of these fish are effective at eliminating mosquito larvae when dense vegetation is present.  Dense vegetation can provide cover for mosquito larvae and make it difficult for fish to locate and consume them.  Reducing excess vegetation in and around the water garden is recommended.

 

Increasing water movement in ponds and water gardens, and eliminating standing water in old tires, gutters, and other water-holding containers are two strong tools in eliminating mosquito-breeding sites. 

Originally Published in Canton Daily Ledger Column on 5-17-2003