Triploid grass carp

Triploid grass carp are sterile (three sets of chromosomes) grass carp stocked as a biological control for submerged aquatic invasives. They feed heavily on hydrilla, pondweeds, and elodea but ignore water hyacinth, water lettuce, cattails, alligator weed, and most floating plants. Stocking rate is 5–15 fish per acre depending on coverage. Sterility prevents establishment of wild populations downstream. Permit required from the state wildlife agency in nearly all jurisdictions. Wrong fish in the wrong pond — e.g., grass carp in a fishery pond — destroys the native vegetation that supports the fishery.