Grass Carp
Grass Carp are prohibited invasive species in Wisconsin. These large herbivorous fish are native to eastern Asia and have been documented in Wisconsin waters.
The species moves toward Wisconsin waters from the Illinois and Mississippi Rivers and is sometimes illegally stocked in private ponds for aquatic plant control.
Scientific Name: Ctenopharyngodon idella
Also known as white amur
- Can grow up to 150 cm (59 inches) in length and weigh up to 80 pounds.
- They have elongated, torpedo-shaped bodies with dark olive coloring that shades to brownish-yellow on the sides and white belly, with large, slightly outlined scales.
Fishing in Wisconsin
Wisconsin River
Big Eau Pleine Reservoir
Lake Poygan
Castle Rock Lake
Spencer Lake
Little Wolf River
Wolf River
Fox River
McDill Pond
Wisconsin River Flowage
What to know
Habitat Distribution
- Native to eastern Asia.
- Found in Wisconsin waters, moving toward Wisconsin waters from the Illinois and Mississippi Rivers.
Key Locations
- Grass carp have been documented in Wisconsin waters including the Mississippi River (Pool 4), Wisconsin River near Mazomanie, Red Cedar River, Milwaukee River, Kinnickinnic River, Menomonee River, and Wind Lake in Racine County.
Specific Spots
- Target shallow, weedy areas with abundant vegetation.
- Look for areas near cattail edges.
Grass Carp FAQ
Answers from onWater's species guide.
What flies work for Grass Carp in Wisconsin?
Effective fly patterns include size 12-16 beadhead woolly buggers (black, olive), size 14-18 beadhead hares ear nymphs, size 18-22 midge patterns, and size 12-14 CDC caddis patterns. Terrestrial patterns like foam ants and rubber-legged hoppers work when fish feed near surface.
When is the best time to fish for Grass Carp in Wisconsin?
Spawning occurs from May to July in fast-flowing water when temperatures reach 17-30°C (63-86°F) - avoid fishing during these spawning periods.
How do you catch Grass Carp in Wisconsin?
Present flies by leading the fish by 10-15 feet, then slowly strip the fly in front of their face. Never set the hook hard - slowly lift the rod to noon and let the fish hook itself. Look for tailing fish (feeding on bottom with tails visible) or cruising fish near cattail edges.
What do Grass Carp eat?
They primarily feed on aquatic vegetation, consuming large amounts of aquatic plants. Young grass carp start as omnivores eating zooplankton and insects before switching to a primarily herbivorous diet at about 26mm length. Adults will also consume terrestrial plants when aquatic vegetation is scarce.
Where do Grass Carp live in Wisconsin?
Native to eastern Asia. Found in Wisconsin waters, moving toward Wisconsin waters from the Illinois and Mississippi Rivers.
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