WOAH: Your goldfish become giant monsters if you release them into the wild

Goldfish are not native to Ohio, so letting them go in streams and ponds can be harmful to local waters

Well that’s not something you see every day.

That goldfish your daughter won at the county fair may have forged an emotional bond that makes it hard to say goodbye. If you love something, let it go. “Swim, sweet Goldie,” she calls out to him as you empty his bowl into your neighborhood pond, “swim like the wind!”

Get that out of your mind. Don’t. Just don’t.

This photo shows one of dozens of goldfish collected during a dam project in Twin Lakes in Parma. Before we inspect a dam to assess repair needs, the water level must be lowered about six feet. So Cleveland Metroparks helped by electroshocking the lake to collect as many fish as possible for safe relocation before we began.

What did we find? Nearly 1,000 great native fish like bulkhead catfish and sunfish. But also goldfish.

Particularly a few very large goldfish.

“…which is enormous for a goldfish.”
“I did see a few of the biggest ones were 2, maybe even 3 pounds. Which is enormous for a goldfish,” said Cleveland Metroparks Aquatic Biologist Mike Durkalec.

Discoveries like this are assumed to be the result of local residents releasing their pet goldfish into the lake. But one fish’s freedom is another habitat’s problem.

“People are surprised they can grow so big and survive in the wild,” Durkalec said. “But they compete with native species and can cause detriment to the environment.” Invasive species can disrupt the habitat’s food chain or consume valuable nutrients upon which native species depend.

Mike had a message for pet owners, no matter what species those pets may be: “People should not release their pets in the wild. Fish or otherwise.”

Photo by Mike Durkalec