Piscicides are
fish poisons.
They are sometimes used in commercial
fish hatcheries or stocked bodies of water when an
undesirable type of fish takes over and becomes the
dominant species. The fish life in a given body of water may be completely or partially killed off by
wildlife managers in order to eliminate an
invasive pest fish species and to allow for native species restoration. This has been needed historically many times in the US.
Ruffe threaten Lake Superior.
Northern Snakeheads threaten the
Patuxent River watershed.
Carp threaten
wetlands in
Idaho. The
Round Goby threatens the
Mississippi River.
Historically plants with piscicidal properties have been used to bring fish to the surface of the water and make them easier to catch. In the US,
rotenonee’s use is restricted if the fish are to be taken for food. Most plant-based piscicides do not harm mammals; instead they damage the gills of fish. Piscicides may be used to kill
predators of commercially grown
shellfish. Other plant based piscicides include
mullein, many
legumes,
Abuta,
chrysanthemums (the source of
Pyrethrum) and
rotenone (obtained from the
derris root). Some non-plant based piscicides also exist such as
Antimycin.