Stocking and Harvesting Fish in Stormwater Ponds


stocking triploid grass carp

Many fish species grow well in stormwater ponds, and there are many advantages to stocking fish in these ponds. Fish help to balance the ecology of the pond by serving as top predators, consuming smaller fish and invertebrates, but they also serve as forage for many attractive animals such as wading birds and osprey. Fish are functional reservoirs for nutrients that have washed into the pond and help the pond capture nutrients carried in runoff. Some fish are herbivores and assist with controlling unwanted aquatic plants. Finally, game fishes stocked in stormwater ponds provide recreational fishing for residents in the community. It must be noted that stormwater ponds are not designed to be recreational fishponds and should not be managed in the same ways as recreational fishponds. Fishing is not the primary service provided by stormwater ponds. Although not ideal, a well-managed stormwater pond can be suitable habitat for several species of fish.

What fish should be stocked in stormwater ponds?
The list of appropriate fish is short and is limited to bream, largemouth bass, triploid grass carp, and blue tilapia.

  1. Bream (Lepomis spp.) refers to several species of "pan" fish that feed predominantly on invertebrates and small fish. Bream provide effective control of aquatic insects, and they serve as prey for largemouth bass. Bream should be stocked at a rate of 500 fish per acre. Both bluegill (Lepomis macrochirus) and shellcracker bream (Lepomis microlophus) are suitable. If both are to be stocked together, they should be stocked at a ratio of 3 bluegill to 1 shellcracker. Bream are best stocked in fall or winter. Other bream species such as green sunfish, pumpkinseed sunfish, and hybrid bream should be avoided.

  2. Largemouth Bass (Micropterus salmoides) are the most sought after freshwater game fish in North America. They feed both on invertebrates and smaller fishes, amphibians and reptiles. In ponds, bream serve as the primary forage for largemouth bass. Given that the pond has an adequate bream population, largemouth should be stocked at a rate of 50 fish per acre in the early spring. A healthy ratio of bream to bass is 10:1.

  3. Triploid Grass Carp (Ctenopharyngodon idella) provide excellent multi-year control of most species of submerged plants. It is recommended that triploid grass carp be stocked at a rate of 20 fish per acre of vegetation when ponds have heavy weed problems. Ponds that have not yet formed large weed populations may be stocked with 5 to 10 fish per acre to prevent weed growth. Grass carp are best stocked in the spring but may also be stocked in the fall.

  4. Blue Tilapia (Oreochromis aureaus) provide aquatic weed control, serve as additional forage for bass, and provide sport fishing for anglers. Unlike triploid grass carp, blue tilapia provide good control of filamentous algae as well as other submerged vegetation. On some occasions when stocked at the maximum rate, blue tilapia will control small floating plants such as duckweed and watermeal. It is recommended that tilapia be stocked in mid to late spring (once water temps are consistently above 60 degrees) at a rate of 200 to 400 fish per acre of pond surface, depending the level of weed growth. Tilapia are tropical fish that do not normally survive South Carolina winters and need to be restocked each year. On occassion, tilapia have been observed surviving through mild winters when water temps remain above 55 degrees F.

Are there any fish that should not be stocked in stormwater ponds?
Fish other than bream, bass, triploid grass carp, and tilapia should not be stocked in stormwater ponds. Catfish, crappie, spotted bass and hybrid bass are predators that compete with largemouth bass and deplete the prey fishes (bream).  Shiners, shad, suckers, and common carp cause other problems ranging from muddy water to competition with other fishes. No aquarium fishes (gold fish, koi, tropical fishes, pacus, oscars, etc.) should ever be released into stormwater ponds because there is the potential for these fishes to be washed downstream into rivers and lakes where they can cause significant damage to native fisheries.  This is the most common way that invasive aquatic animals are introduced.

How do I find fish for my pond?
Check with your local farm supply stores because these businesses often sponsor "fish days" when you can order and purchase the fish you need, especially if you are seeking small quantities. Otherwise, consult the Aquaculturist Vendors List maintained by the SC Department of Natural Resources. This list contains all of the licensed aquaculture facilities in the state with their contact information and the species of fish that they sell. SC Aquaculturist Vendors List.

Should I harvest fish from my stormwater pond?
Youth fishing in stormwater pondYes. In order to maintain a good balance of fish, it is recommended that bream and bass be harvested from the pond annually. This amounts to 40 lbs. of bream per acre per year and 10 lbs. of bass per acre per year.

**BE AWARE** There is potential for toxin contaminants and other pollutants to be accumulated in the tissues of these fish. A primary function of stormwater ponds is to trap and treat pollutants washing from roads and lawns in the community. Little research has been done to show how much pollution is accumulated in fish tissues in stormwater ponds, but it is not advised for residents to eat fish harvested from stormwater ponds. Composting fish for use in the home garden does not pose a significant threat. If anglers do catch fish, it is strongly advised that they use hand sanitizer or wash their hands thoroughly after fishing because stormwater ponds often have high levels of fecal bacteria and other pathogens that can make anglers sick.

I am experiencing a fish kill. Who do I contact to determine the cause?
Stormwater ponds are not designed to be fishponds. Their design and purpose make them prone to turnover events, rapid temperature swings, periods of low water, and poor water quality. These conditions often result in poor fish health and possible fish kills. To determine the cause of your fish kill, refer to the Fish Kill/Fish Health Section of this website or call your local Clemson Extension office or Department of Health and Environmental Control Environmental Quality Control office.