Grass Carp
Invasive speciesRecorded in 4 lakes
Grass Carp appears on state infested-waters lists for 4 surface waters. Boaters and anglers moving gear in or out of those lakes carry a clean-drain-dry obligation under state law. 4 lakes — narrow enough that aggressive containment is still on the table. Most upper-Midwest invasives that established here did so quietly over a decade before anyone noticed, so a low number today is not a guarantee for tomorrow.
The presence of Grass Carp does not change a lake's clarity, phosphorus or algae readings, which measure the water itself, not the species living in it. Invasive presence is still worth reading alongside those numbers.
Lakes with Grass Carp
| Lake | County | State | Depth |
|---|---|---|---|
| Spring Lake | Dakota | MN | 17 ft |
| Nelson Lake | Goodhue | MN | - |
| Robinson Lake | Wabasha | MN | - |
| Grey Cloud Slough Lake | Washington | MN | - |
Frequently Asked Questions
How many lakes have grass carp?
Grass Carp is recorded in 4 measured lakes: 4 in Minnesota. 4 of them carry a state infested-waters listing or an established population.
Does grass carp affect water quality?
An established invasive population can change how a lake works — altering nutrient cycling, displacing native species, and shifting water clarity. Clarity is the one to watch: filter-feeders can make water read clearer on a Secchi disk without any drop in nutrient loading, so a lake with grass carp is worth reading alongside its clarity number rather than through it.
Invasives Found With Grass Carp
More on invasive species and lake health
Zebra mussel counts from the lakes LakeQuality tracks, the counties that show up most often, and the Clean, Drain, Dry rules that still matter.
How nutrient and algae readings are read against EPA ecoregion condition classes, what each class means in the water, and why a clean reading is not a clearance.
Before you buy lakefront, check the water: clarity trend, nutrient impairment, algae advisories, invasive species, and depth — a data-backed checklist.
Source: EPA National Aquatic Resource Surveys, 2026.