Connecticut Department of Energy & Environmental Protection

Grass Carp (Ctenopharyngodon idella) - Introduced

Grass carp.

A 24-inch adult grass carp.

Identification. A large fish. Similar to the common carp, but with a more streamlined body. No spots or blotches. Barbels absent. Snout is short, and eye is positioned oddly low on the head. Caudal peduncle thick (and powerful) compared with depth of fish. At least one spine at front of dorsal and anal fins. Soft dorsal rays 7-8. Anal fin set back on body, similar to suckers. Soft anal rays 7-11. Brown to dark gray on the back fading to bronze or gray on the sides and cream on the belly.

Size. Commonly 20 to 32 inches. Conn. max. observed size 44 inches. Max. reported size 5 feet, 100 pounds.

Giant grass carp.

This large grass carp was taken from Lake Zoar, Oxford. CT DEEP Fisheries Division file photo.

Distribution. Native to China and Siberia. Introduced throughout North America. In Connecticut, grass carp typically occur only in small ponds where they have been stocked under special permit. Escapees may be encountered elsewhere. The only large public lake currently being stocked with grass carp is Ball Pond (New Fairfield).

Grass carp distribution map.

Habits. Grass carp prefer larger water bodies with abundant vegetation and slow-moving water. They are tolerant of low dissolved-oxygen levels. This is the only fish species in Connecticut that is primarily vegetarian. Although challenging, they can be caught by angling with various vegetable baits such as cherry tomatoes, dough balls, and even french fries.

Comments. Grass carp are strong swimmers that often leap several body lengths out of the water when spooked. They have long been introduced in the United States to control nuisance aquatic vegetation. They have the ability, however, to completely denude lakes of vegetation when their densities are high. For this reason, their introduction is strictly regulated in Connecticut and only sterile fish may be imported into the state. Dots on the state range map indicate private ponds where permits were recently approved to stock grass carp (2003-05). 

 

Text and images adapted from Jacobs, R. P., O'Donnell, E. B., and Connecticut DEEP. (2009). A Pictorial Guide to Freshwater Fishes of Connecticut. Hartford, CT. Available for purchase at the DEEP Store. The fish distribution maps were created in 2009. For updated fish distributions please use the CT DEEP Fish Community Data Interactive Map.