Giant goldfish are becoming a problem in Minnesota lakes, and wildlife officials are warning fish owners who no longer want to care for their pets not to flush them down the toilet or dispose of them in lakes, ponds or waterways.
Donate them instead.
"They can grow to be the size of dinner plates in these waters," said Sharon Moen, a spokesperson with the Minnesota Sea Grant.
Moen said wildlife officials have recovered giant goldfish, piranha, Amazonian catfish, koi and even a caiman — a reptile related to alligators — from Minnesota waterways. A pond in Duluth was taken over by goldfish, she said.
Goldfish have been recovered from Powderhorn Lake in Minneapolis; the Department of Natural Resources also caught one near Albert Lea that was 9 to 11 inches long.
"It's not that common," she said. "But it happens more than you would think."
Releasing fish and plants from aquariums can harm Minnesota waters and native species. Fish can carry diseases, reproduce quickly and root up native plants to find food.
It is illegal to release aquarium plants and fish in Minnesota, according to the Department of Natural Resources. Aquarium fish can carry diseases that can kill native fish. Invasive plants such as water hyacinth and yellow iris can clog waterways and snag boat propellers.