Don’t be Koi, Utah: Pet fish shouldn’t go into ponds or lakes

Jul 19, 2021, 1:33 PM

Photo of Utah Lake [Photo Credit: Canva Images]...

Photo of Utah Lake [Photo Credit: Canva Images]

SALT LAKE CITY — Utah pet fish should never wind up in a pond or a lake, advice that’s even more important after a cautionary tale from Minnesota. 

The city of Burnsville, Minnesota warned of the dangers related to releasing a pet fish into the wild. The city tweeted, “[The goldfish] grow bigger than you think and contribute to poor water quality.”

Utah pet fish pose a big problem in waterways

Just last year, The Utah Division of Wildlife Resources found two waterbodies in the state to have pet fish illegally dumped in them. DWR reported when people dump different species of fish into a waterbody it can wreak havoc on the ecosystem. 

This year, a man caught a nearly 17-pound koi in a small Utah County pond, a type of carp that the DWR said should have never been there.

According to KSL TV, DWR confirmed koi fish are invasive, and typically end up in a pond from someone dumping their pet fish in.

DWR also warned fish owners that dumping any species of fish into a pond or lake is illegal and can be harmful to animals and the environment.

Goldfish and water quality in the “wild”

When DWR found goldfish at Jackson Flat, they believed someone reluctant to kill their unwanted pet dumped it in the water there instead. However, goldfish can quickly harm an ecosystem by rapidly taking over a waterbody. 

These illegal introductions typically ruin fisheries and threaten the species that live there.

“We typically have a few incidents a year where fish are illegally introduced each year,” Faith Heaton Jolley, public relations officer for DWR, said. 

Pet fish can also out-compete the native fish in a waterway.

“It can also introduce new diseases that can negatively impact, or destroy, the native fish population, in addition, adding to poor water quality,” Jolley said. 

Utah wildlife officials: Don’t ditch your pet fish in Utah lakes or ponds

“Basically it is illegal to introduce fish, including pet fish, into Utah water bodies,” Jolley explained. The happy fairytale of our fish swimming free after a life in a bowl isn’t as happy as it sounds. 

Why it’s bad

According to DWR, your pet could: 

  • Slowly starve to death
  • Become a tasty meal for a predator
  • Introduce harmful pathogens or parasites to native populations
  • Outcompete native species for limited food resources
  • Prey directly on native species
  • Survive, multiply and become an invasive species

Fisheries ruined by aquarium fish require expensive chemical treatments and hours in planning and restoration.

How you can help: Don’t release your pet fish 

DWR said the best way you can help is: 

  1. Don’t ditch a fish — whether it’s an unwanted pet or a living fish from another waterbody
  2. Dispose of aquarium fish properly (call us if you need help)
  3. Report observations of invasive fish to us by calling 1-800-662-3337
  4. Report observations of illegal introductions by calling 1-800-662-3337


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Don’t be Koi, Utah: Pet fish shouldn’t go into ponds or lakes