Undated(KROC AM News) - One pet goldfish may have caused a large fish kill in a southern Minnesota lake last month.

The Minnesota Dept of Natural Resources says the kill happened in Lake Elysian in Waseca County and involved thousands of common carp.

Tests have linked the source to a virus that likely came from a pet goldfish that was either released or escaped from a pond and made its way to the lake or a connecting waterway. The virus is called KHV, or koi herpesvirus.

This is the first documented case of its kind involving wild fish in Minnesota.

Experts say the virus does not affect humans and is not believed to affect other fish species. Goldfish can be carriers of the virus but typically do not show signs of the disease.

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

The DNR reminds the public that releasing ornamental fish into the wild has consequences and is illegal.

“Many people don’t realize that koi are essentially just colorful carp so ultimately they are the same species and not native to Minnesota,” said Craig Soupir, DNR’s Waterville area fisheries supervisor. “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.”