Chinese Mystery Snail
Invasive SpeciesFound in 494 lakes
Chinese Mystery Snail appears on state infested-waters lists for 494 surface waters. Boaters and anglers moving gear in or out of those lakes carry a clean-drain-dry obligation under state law. A 494-lake footprint means Chinese Mystery Snail prevention has shifted from "stop the spread" to "manage the new normal." Watercraft-inspection programs at boat launches and shoreline-management practices on individual lakes are doing most of the active prevention work.
The presence of Chinese Mystery Snail does not directly change a lake's letter grade — the grade measures the water itself, not the species living in it. Invasive presence is still worth reading alongside the grade.
Lakes with Chinese Mystery Snail
| Lake | County | State | Grade | Depth |
|---|---|---|---|---|
| Big Cedar Lake-North Site-Near West Bend | Washington | WI | A | 105 ft |
| Big Cedar Lake-South Site-Near West Bend | Washington | WI | A | 105 ft |
| Okauchee Lake | Waukesha | WI | A | 90 ft |
| Powers Lake | Kenosha | WI | A | 33 ft |
| Lac Courte Oreilles Lake | Sawyer | WI | A | 90 ft |
| Whitefish Lake | Sawyer | WI | A | 105 ft |
| Big Sand Lake | Burnett | WI | A | 55 ft |
| Sand Lake | Sawyer | WI | A | 50 ft |
| Ashegon Lake | Sawyer | WI | A | 56 ft |
| Koonz Lake | Shawano | WI | A | 40 ft |
| Gaslyn Lake | Burnett | WI | A | 12 ft |
| Malone Lake | Shawano | WI | A | 31 ft |
| Sams Lake | Shawano | WI | A | 13 ft |
| Mission Lake | Shawano | WI | A | 44 ft |
| Bealeau Lake | Shawano | WI | A | 24 ft |
| Mole Lake | Forest | WI | A | 17 ft |
| Wind Lake | Polk | WI | B | 7 ft |
| Boulder Lake | Vilas | WI | B | 23 ft |
| Spider Lake | Vilas | WI | B | 43 ft |
| Pickerel Lake | Forest | WI | B | 19 ft |
| Pickerel Lake | Oconto | WI | B | 10 ft |
| Pickerel Lake | Vilas | WI | B | 26 ft |
| Carpenter Lake | Vilas | WI | B | 16 ft |
| Beaver Dam Lake | Barron | WI | B | 106 ft |
| Balsam Lake | Polk | WI | B | 37 ft |
| Silver Lake | Barron | WI | B | 91 ft |
| Silver Lake | Vilas | WI | B | 19 ft |
| Silver Lake | Forest | WI | B | 20 ft |
| Plum Lake | Vilas | WI | B | 57 ft |
| Whitefish Lake | Oneida | WI | B | 33 ft |
| Whitefish Lake | Douglas | WI | B | 102 ft |
| Bass Lake | Oneida | WI | B | 20 ft |
| Bass Lake | Washburn | WI | B | 31 ft |
| Bass Lake | Oconto | WI | B | 40 ft |
| Bass Lake | Barron | WI | B | 14 ft |
| Bass Lake | Vilas | WI | B | 15 ft |
| Bass Lake | Lincoln | WI | B | 40 ft |
| Ashippun Lake | Waukesha | WI | B | 35 ft |
| Clear Lake | Rusk | WI | B | 74 ft |
| Clear Lake | Polk | WI | B | 26 ft |
| Clear Lake | Oneida | WI | B | 95 ft |
| Pioneer Lake | Vilas | WI | B | 27 ft |
| Little Spider Lake | Vilas | WI | B | 23 ft |
| Bone Lake | Polk | WI | B | 43 ft |
| Indian Lake | Oneida | WI | B | 26 ft |
| Tom Doyle Lake | Oneida | WI | B | 30 ft |
| Bear Lake | Oneida | WI | B | 20 ft |
| Bear Lake | Barron | WI | B | 87 ft |
| Bear Lake | Waupaca | WI | B | 62 ft |
| Bear Lake | Oconto | WI | B | 20 ft |
Showing 50 of 494 infested lakes.
Frequently Asked Questions
How many lakes have chinese mystery snail?
Chinese Mystery Snail has been documented in 494 graded lakes: 494 in Wisconsin.
Does chinese mystery snail affect water quality?
Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with chinese mystery snail should be monitored for changes in water quality over time.
Invasives Found With Chinese Mystery Snail
Co-occurs in 217 lakes · 420 total
Co-occurs in 199 lakes · 362 total
Co-occurs in 154 lakes · 247 total
Co-occurs in 144 lakes · 275 total
Co-occurs in 69 lakes · 667 total
Co-occurs in 23 lakes · 95 total
More on invasive species and lake health
Zebra mussel counts from the lakes LakeQuality grades, the counties that show up most often, and the Clean, Drain, Dry rules that still matter.
How lakes are graded A–F on nutrients and algae using EPA ecoregion condition classes, what each letter means in the water, and why an A 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.