Carver County Minnesota Water Management

Minnesota Officials Remove 50,000+ Invasive Goldfish From Big Woods Lake


Over 50,000 goldfish removed from Minnesota waters in just one location.

Just when you didn't think 2020 could get any weirder, officials with the Carver County Water Management Association in Minnesota announced they have removed 50,000 goldfish from a creek in Chaska. Images online after the haul show enough of the pet store staple to fill the back of a pickup truck.

MPR News reports that the goldfish were removed from an inlet that connects to Big Woods Lake. The small, brightly colored fish were first detected in the lake, which is southwest of Minneapolis, last April.

Now, they're thriving due to a lack of predators and poor water quality that other species would struggle in, setting off a huge management and removal program.

"They're perhaps the only vertebrate animals that can live without any oxygen, which is remarkable," the organization's aquatic invasive coordinator Andrew Dickhart told MPR news. "They can go what we call totally anaerobic and they just live off sugars and produce alcohol."


Of course, the biggest question on everyone's mind is how the non-native animals got into the lake in the first place.

"The most likely scenario is that somebody or a couple people released goldfish and they're exceedingly hardy fish," Carver County Water Management Spokesperson Madeline Seveland told MPR News.

On October 26, staff with Carver County Water Management netted an estimated 50,000 goldfish out of the creek, but plenty more remain there and in the lake. To remove them completely, officials need to study their movements to figure out where they are spawning. They have put in place a three-year plan to do just that. The first part of it involves tagging and monitoring the movements of 500 goldfish.

"If we're going to remove the fish, we need to keep track of a percentage of the population that we're removing, until we can get it down to a certain level where that population may no longer be harmful to the lake ecosystem," Dickhart said.


Carver County Water Management plans to use electrofishing to get a better grasp on the populations within the lake first. Once they have a better idea of then numbers, and where they are spawning, they can begin more population control efforts.

Possible solutions include building barriers to cut off access to spawning areas and stocking predatory fish to eat the invasive animals. In the meantime, they are asking the public to not release unwanted pets into natural water bodies, but to instead take them to a pet shop or aquarium.

"As we focus on removing goldfish, it is important that we don't have new introductions. You can help by spreading the word about what do to if you have a pet you no longer want or can't care for," the water management department's website reads. The best thing to do is find it a new home. Donate it or take it to a surrender event. Surrender events are often hosted by the MN Aquarium Society."

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