Thousands of fish likely died in MN lake because someone released their pet goldfish

It's illegal to release goldfish into the wild in Minnesota.

A bunch of fish died in a Minnesota lake last month, and now officials think the fish kill could have been caused by a pet goldfish. 

The Minnesota DNR and the University of Minnesota say koi herpesvirus was the main cause of thousands of carp dying in Lake Elysian in Waseca County in late June. 

“What this incident tells us is the virus can be introduced by human action – a goldfish or koi was likely released from a home aquarium or pond into Lake Elysian or a connecting waterway," Craig Soupir, DNR’s Waterville area fisheries supervisor, said in a statement. 

This is the first documented case of it in a wild fish population in Minnesota. The DNR says the virus can cause disease in koi and common carp, while goldfish can be carriers of it without showing signs they have the disease. 

“The virus can be present in a lake without causing a fish kill, at least not until the right conditions are present,” DNR fisheries pathology lab supervisor Ling Shen said in a statement. “KHV is highly contagious, and as we’ve seen, very capable of causing large-scale die-offs of common carp.”

The koi herpesvirus (KHV) doesn't affect humans, and it's not believed to affect other fish species. 

Releasing your pet goldfish is illegal

The DNR is reminding people that if you're sick of your pet fish, you shouldn't release it into the wild – it's actually illegal. 

Other groups have also encouraged people not to flush your pet fish down the toilet. 

Goldfish and other ornamental fish aren't native to Minnesota, so if you're looking to dispose of one of these fish you should contact the DNR or a local humane society.

The most common non-native fish released in Minnesota are goldfish, common carp-koi and the Oriental weatherloach, Minnesota Sea Grant says

To learn more about invasive species in Minnesota, click here

Next Up

Dean Evason

Wild fall flat against Predators, lose first game of season

The Wild couldn't stay out of the penalty box in a 5-2 loss.

Screen Shot 2021-10-24 at 10.11.36 AM

Search for Wisconsin woman whose vehicle was found near Hinckley

Ashley L. Miller, 33, was reported missing on Sep. 24 after her vehicle was found without her in it.

Dak Prescott

Report: Dak Prescott will be 'ready to go' for matchup with Vikings

The Dallas quarterback is expected to be available for next Sunday's showdown.

Eddie Rosario

Where Eddie Rosario's championship series heroics rank since 2000

The former Twin put together an all-timer to help the Braves reach the World Series.

plane, Piper PA-32

2 dead after plane crashes near residence in rural Wisconsin

The aircraft also struck the house during the crash.

Screen Shot 2021-10-23 at 9.38.43 PM

1 dead after van crashes and lands on Highway 100 in Brooklyn Center

Northbound Highway 100 was shut down following the crash Saturday night.

Jess Peterson

Woman killed in crash ID'd as 'bad ass biker chick' with 'giving spirit'

The 30-year-old died in a motorcycle crash on Oct. 19.

Karl-Anthony Towns

Timberwolves' defense fuels win over Pelicans

The Wolves' have bought in on the defensive end as part of a 2-0 start.

Minnesota Wild

Ryan Hartman's OT goal helps Wild stay undefeated

The Wild improved to 4-0 with a win over the Ducks.

Mar'Keise Irving / Gopher Football

Gophers pound Maryland to stay in Big Ten West race

Four different players scored a rushing touchdown in a 34-16 victory over Maryland.


Screen Shot 2021-07-09 at 9.29.45 AM

This leviathan is why you shouldn't release pet goldfish into lakes

The gargantuan goldfish was found in Burnsville waters.

Screen Shot 2019-04-20 at 9.13.40 AM

Invasive goldfish population spikes in Chaska chain of lakes

Goldfish aren't good for Minnesota's waterways.

Thousands of mink freed from that farm have died, fur group says

The group is offering a $10,000 reward for information on who's responsible.

It's still fall, and someone had to be rescued while ice fishing in MN

"Folks, it is not even close to safe to venture out on the ice."

Someone's jamming fish hooks in meat and feeding it to dogs

The fish hooks were found hidden in chunks of meat.