Goldfish a Problem for Local Lakes

Goldfish in a temporary water storage area
Goldfish just visible in a temporary water storage area

Goldfish kept as pets at someone’s home are a common site, but goldfish found at a construction site is not expected. Yet, that is what happened recently during construction at the 169 bridge site by Nine Mile Creek.The goldfish did not come from Nine Mile Creek, but had traveled from a pond between a condo complex and another building.

Goldfish are not native to Minnesota. When released to natural water-ways, goldfish are destructive to native species and their habitats. They stir up the bottom sediment when they eat, increasing the cloudiness of the water and impacting aquatic plant growth. Goldfish can survive in low oxygen conditions and can tolerate larger fluctuations in water temperature. This allows them to thrive and out-compete native fish species in certain conditions, reducing the biodiversity of the water body. The recent story of goldfish in Wood Lake Nature Center in Richfield is a prime example of this.

Goldfish in the wild, By George Chernilevsky [CC BY-SA 3.0]
If you have an aquarium animal or plant that you no longer want, contact a retailer or vet to find out how to safely and humanely get rid of it. It is illegal to release most non-native species, including goldfish, into the wild in Minnesota.

Nearly all of our lakes and ponds are connected. What gets dumped, or even intentionally placed, into one pond has the potential to travel and spread to another, as is the case of the fish traveling from the pond to the construction site by Nine Mile Creek. “Education is important in reducing the spread of invasive species”, states Education and Outreach Manager Erica Sniegowski. “Dumping goldfish and other aquarium plants and animals can have significant impacts to our local water bodies.”

For more information about aquatic invasive species, visit the Minnesota DNR’s aquatic invasive species page and the page on invasive species laws. Ontario’s Invading Species Awareness Program also has additional information on goldfish in the wild.