Triploid grass carp, Diploid grass carp, white amur….not very alluring names for a fish that one may want to stock their natural pond with. Grass carp (Ctenopharyngodon idellus) are not really the greatest looking fish to keep in your pond and on top of that they are certainly not easy to acquire, and would probably require a permit to keep in your pond. Who wants to do paper work just to get a fish? Why bother!?
I’ll tell you why to bother with these fish: aquatic weed and algae control for your natural pond or lake.
Better yet, organic aquatic weed and algae control.
Oh, so suddenly these fish are appealing right? You bet!
The Grass Carp is a somewhat misunderstood fish that has a lot of misinformation attached to it. Even the name, Grass Carp, to pond keepers will conjure up images of fish that look like koi or common carp but the physical similarities are few. The Grass Carp has a sleek elongated body with silver/white/gray coloration, a broad head, no barbs on the mouth area, and finnage that is different from the carp or koi. The Grass Carp really looks more like a huge minnow than a carp!
This fish has been around for a very long time and has served mankind on many levels. Grass carp is a native to China and the Chinese have used these fish to control weed growth in rice paddies and also as a food source for about 2000 years. Marco Polo made mention of this fish in his travels and for close to 300 years the Russians have utilized the white amur / grass carp for aquatic weed and algae control to. This hardy vegetarian river fish has provided an economical cost effective solution for algae and weed control across the globe. In more recent times the grass carp was used in Egypt to clean up the Nile River itself! In modern times this quick growing, great tasting, fun sport fish is outlawed in much of the U.S. because of environmental impact misinformation regarding this fish.
Grass Carp were introduced to the United States in 1963, and today is considered an invasive species. The belief that grass carp will reproduce out of control and destroy ecosystems led Arizona, California, Colorado, Connecticut, Georgia, Idaho, Illinois, Indiana, Louisiana, Maine, Maryland, Michigan, Minnesota, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, Wisconsin, and Wyoming to make them illegal; with most of the remaining states requiring permits to stock these fish. This misunderstood fish, according to fisheries biologist really shares little of the traits that its carp namesake has.
The grass carp does not muddy the waters of ponds or lakes in its efforts to eat plant materials; like its cousin the European carp. The grass carp actually tends to “mow” plants, eating them from the top down because of the way its mouth is placed. The grass carp does not tear out aquatic plants by rooting and muddying the water. Grass carp also do not prey upon invertebrates, fish eggs, or small fish; they much prefer water weeds and thin leaved pond weeds. With enough food supply the grass carp can get to be a pretty good size. In the first 2 years they can grow incredibly fast, up to 2 inches per month, and weigh up to 20 pounds. Average adult weight is about 40 pounds at 4 feet length, but some full grown grass carp have weighed in at 100 pounds!
Grass carp do not destroy nesting areas of waterfowl as may be reported, and prefer moving water as their natural habitat, like rivers. Many biologists report that grass carp can only reproduce in river systems as the eggs need river conditions to be successful. Successful spawns in standing water is impossible yet the practice of sterilizing these fish is commonplace. The sterilized form of the grass carp is a triploid carp, fertile grass carp are diploid carp. These fish live about 10 years but can live much longer under the ideal conditions. During winter months the Grass Carp goes through a period of dormancy. When water temperatures stay about 65F-70F these fish feed intensely, but may be shy about feeding in areas of human activity like swimming areas or docks.
To obtain these fish for pond stock contact your state’s Division of Wildlife to be directed on how to obtain them in your area and to have your pond evaluated to see if you are indeed eligible to keep the Grass Carp. A rough diagram of your pond may be asked for. A basic requirement for most ponds that want to stock these fish is that the ponds are large enough, and do not have any areas that can allow for escape of these fish into other bodies of water. If you have an inline pond that the fish can easily escape from you will not likely be permitted to keep the Grass Carp. When introducing Grass Carp you may only be allowed to stock a few and these guidelines will depend on your state’s regulations. About 10 grass carp per acre is a good starting stock level. Once stocked in a pond they are not easy to get out. Grass carp are very effective at controlling weeds, but the results may take a little time to become apparent, but fear not these fish do their jobs eating up to 3X their own body weight daily!
So if you want to say goodbye to costly ineffective chemical treatments for your pond’s weed and algae problem, then the white amur (grass carp) may be your solution. Very effective “worker” fish and they even can provide some sport from your pond too, being known for putting up a good fight and being smart as trout. With their long life spans they could even become aquatic friends to you, keeping your ponds undesirable plant growth in check for you. Be sure to check your state’s laws concerning these amazing fish and stock wisely.
All copyrights to this material belong to Mike Gannon.
