Spiny Waterflea

Invasive SpeciesFound in 93 lakes

Spiny waterflea is a small zooplankton invasive that disrupts the food web by competing with native zooplankton — the base of the food chain for many small fish. Documented in 93 lakes. 93 infested lakes is enough to require active prevention work statewide. The species is established in pockets but not ubiquitous.

The presence of Spiny Waterflea does not directly change a lake's LakeGrade rubric score — the grade measures the water itself, not the species inhabiting it. But invasive presence is a meaningful adjacent signal worth reading alongside the grade.

Total Lakes

Minnesota

Wisconsin

Lakes with Spiny Waterflea

Lake	County	State	Grade	Depth
Clearwater Lake	Cook	MN	A	65 ft
Trout Lake	Cook	MN	A	77 ft
Pine Lake	Cook	MN	A	113 ft
Burntside Lake	St. Louis	MN	A	126 ft
Gunflint Lake	Cook	MN	A	200 ft
Flour Lake	Cook	MN	A	75 ft
Snowbank Lake	Lake	MN	A	150 ft
Mcfarland Lake	Cook	MN	A	-
Greenwood Lake	Cook	MN	A	112 ft
Little Gunflint Lake	Cook	MN	A	200 ft
Superior Lake	Cook	MN	A	-
Superior Lake	St. Louis	MN	A	-
Butternut Lake	Forest	WI	A	42 ft
Whitefish Lake	Douglas	WI	A	102 ft
Whitefish Lake	Douglas	WI	A	102 ft
Stormy Lake	Vilas	WI	A	63 ft
Bardon Lake	Douglas	WI	A	102 ft
Plum Lake	Vilas	WI	A	57 ft
Spider Lake	Vilas	WI	A	43 ft
Mille Lacs Lake	Aitkin	MN	B	42 ft
Red Rock Lake	Cook	MN	B	64 ft
Devil Track Lake	Cook	MN	B	50 ft
Sucker Lake	Lake	MN	B	111 ft
Shagawa Lake	St. Louis	MN	B	48 ft
Namakan Lake	St. Louis	MN	B	150 ft
Ml-Peterson Lake	Mille Lacs	MN	B	42 ft
Ml-Nw Lake	Aitkin	MN	B	42 ft
Ml-Thains Lake	Mille Lacs	MN	B	42 ft
Ml-Ce Lake	Aitkin	MN	B	42 ft
Ml-Se Lake	Mille Lacs	MN	B	42 ft
Ml-Vineland Lake	Mille Lacs	MN	B	42 ft
Little Lake Deep	Cook	MN	B	-
Ml-Malone Lake	Mille Lacs	MN	B	42 ft
Ml-Garrison Lake	Aitkin	MN	B	42 ft
Ml-Nshore Lake	Aitkin	MN	B	42 ft
Ml-Ne Lake	Aitkin	MN	B	42 ft
Ml-Seventeen Lake	Aitkin	MN	C	42 ft
Teal Lake Deep	Cook	MN	C	-
Namakan Lake	St. Louis	MN	C	150 ft
Rainy Lake	St. Louis	MN	C	161 ft
Sand Point Lake	St. Louis	MN	C	184 ft
Namakan Lake	St. Louis	MN	C	150 ft
Rainy Lake	St. Louis	MN	C	161 ft
Crooked Lake	Lake	MN	C	165 ft
Mille Lacs Lake	Mille Lacs	MN	C	42 ft
West Vermilion Lake	St. Louis	MN	C	76 ft
Rainy Lake	Koochiching	MN	C	161 ft
Basswood Lake	Lake	MN	C	111 ft
Fall Lake	Lake	MN	C	32 ft
East Twin Lake	St. Louis	MN	C	22 ft

Showing 50 of 93 infested lakes.

Frequently Asked Questions

How many lakes have spiny waterflea?

Spiny Waterflea has been documented in 93 graded lakes: 81 in Minnesota, 12 in Wisconsin.

Does spiny waterflea affect water quality?

Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with spiny waterflea should be monitored for changes in water quality over time.

Invasives Found With Spiny Waterflea

Zebra Mussel

Co-occurs in 49 lakes · 688 total

Eurasian Watermilfoil

Co-occurs in 20 lakes · 859 total

Chinese Mystery Snail

Co-occurs in 11 lakes · 493 total

New Zealand Mud Snail

Co-occurs in 7 lakes · 7 total

Faucet Snail

Co-occurs in 7 lakes · 39 total

Round Goby

Co-occurs in 7 lakes · 19 total

Source: EPA National Aquatic Resource Surveys, 2026.