WIND LAKE -- A single fish known as a grass carp put residents in Wind Lake in Racine County on alert. Officials with the Wisconsin Department of Natural Resources said it's an invasive species -- and illegal in the state.
"We've been responsible, for the last 35 years, for improving the water clarity and water quality," said Kathy Aron of the Wind Lake Management District.
For decades, people like Aron have been keeping Wind Lake clean and healthy. That was until Aug. 4, when a bow angler landed a grass carp.
To laymen, it is just another fish. But to experts, it is a major red flag.
"They're native to eastern Asia," said Bob Wakeman with the DNR. "So a long way from home. They eat aquatic vegetation...turn systems from a plant-dominated lake, to an algae-dominated -- and that's not a good thing."
Asian carp are an invasive species that could fundamentally change the lake's ecosystem.
"Well, you might be ringing up fish today, but you might not be tomorrow," Aron said.
Weeks after the finding, the DNR and lake managers asked fishermen to keep an eye out.
"I am concerned that an invasive species is going to wreak havoc on the whole ecosystem," said Neale Robinson, fisherman.
It wasn't immediately clear how the grass carp got into Wind Lake, or if there were more in the water. Early evidence led investigators to believe someone just threw it in, but until this gets resolved, officials urged everyone to be on the lookout.
DNR officials told FOX6 News they took the fish to the lab and found out it was sterile, so odds are good it was not reproducing.
But again, that does not mean there are not others like it in the lake.
CLICK HERE if you would like to learn more about invasive species from the Wisconsin DNR.