Rotenone Can Remove Undesirable Fish From a Pond

Sometimes a pond manager wants to change a fishery in a pond by removing existing fish and restocking other fish. This commonly occurs when a pond with fish will be stocked with small fingerlings or when a pond is dominated by bullheads, common carp or stunted bream. Stocking small fingerlings into an existing fish population often gives poor results because existing fish out compete or eat small fingerlings. When overabundant, bullheads and common carp increase clay turbidity of a pond and reduce sport fish production. When bream are overabundant, they interfere with largemouth bass recruitment by eating too many bass eggs and fry, and their small size makes them inappropriate for human consumption and undesirable for angling. A pond manager basically has three options to remove existing fish: drain the pond, stock plenty of large predatory fish (adult largemouth bass primarily are used for this purpose) or treat the pond with a piscicide (chemical that kills fish). Rotenone is the piscicide most often used to kill fish.