Football-sized goldfish take over lake after decades of people dumping unwanted pet fish

‘They grow bigger than you think and contribute to poor water quality by mucking up the bottom sediments and uprooting plants,’ warns Minnesota town

Conservationists in Minnesota have requested the general public stop releases pet goldfish into lakes and other bodies of water as they are now considered to be an invasive species.

The city of Burnsville, a suburb of Minneapolis, shared some images of an incredibly large goldfish, the size of an American football, that was discovered in a local lake after being let loose.

“Please don’t release your pet goldfish into ponds and lakes! They grow bigger than you think and contribute to poor water quality by mucking up the bottom sediments and uprooting plants. Groups of these large goldfish were recently found in Keller Lake,” the city tweeted on 9 July.

Pet goldfish living in wild waters is not a new problem, as The New York Times date the phenomena of goldfish being deemed as “disposable” back to the 1800s. This when the trend of giving them out as prizes at fun fairs is believed to have begun.

“You see goldfish in the store, and they’re these small little fish,” Burnsville natural resources specialist Caleb Ashling told The Washington Post.

“When you pull a goldfish about the size of a football out of the lake, it makes you wonder how this can even be the same type of animal.”

In 2020, 30,000 to 50,000 abandoned goldfish were removed from the waters in nearby Carver County, Minnesota. In a statement about the removal process, they also said that goldfish can be used as bait, which contributes to the problem.

“A few goldfish might seem to some like a harmless addition to the local water body – but they’re not,” said the Minnesota Department of Natural Resources early this year.

They explained a considerable amount of work goes into monitoring and managing the types of fish living in Minnesota’s waters. This is done to “protect the waters we love”.

The problem has been recorded in other parts of Minnesota, Washington state and other countries across the world, such as Canada and Australia.

The U.S Fish and Wildlife Service say that billions of dollars in damage is done by invasive species, such as goldfish, each year.

An expert trusted with tackling Burnsville’s problem said it can difficult to conceptualise how a tiny fish can cause so much destruction.

Caleb Ashling, a natural resources, specialist told The Washington Post, “Goldfish have the ability to drastically change water quality, which can have a cascade of impacts on plants and other animals.”

He acknowledged that people were thought they were doing a good thing but ultimately, they were causing massive problems for the wider eco system.

“People are trying to be nice, but they don’t realise that goldfish can have a lot of unintended consequences,” he told The Post. “Most people really care about their lakes and ponds, but you may be causing problems you weren’t aware of if you let them go there.”