Grass Carp

(Ctenopharyngodon idella)

Physical Description

The body of a grass carp is oblong shaped with a slightly flattened head and moderately small eyes centered on the side of the head. They are covered with large overlapping scales, and coloration varies from blackish to olive-brown with brassy or silvery-white on the sides and belly. Scales on the back and sides are outlined by pigment giving a cross-hatched effect.

Preferred Habitat

Grass carp prefer large, slow flowing water bodies and spawn in large rivers with moderate currents. Egg survival and larval development is best in waters at 64° Fahrenheit, but adults can tolerate water temperatures ranging from 32 to 100° Fahrenheit.

Diet

Grass carp feed on aquatic plants but can also consume detritus, insects, small fish, earthworms and other invertebrates in the absence of aquatic vegetation. This species can consume up to 40 percent of their body weight per day. By eating such huge quantities of plant biomass, they can significantly alter the composition of habitat by reducing food sources, shelter and spawning areas for native fish. Also, because they can only digest about half of the plant material that they consume each day, the remaining material is expelled into the water, enriching it with nutrients which promotes algal blooms.

Size

Grass carp mature in 2 years, but it can take them more than a decade to grow to a maximum size of more than 80 pounds.

Quick Facts

Origin: Large rivers and lakes in eastern Asia, from southern Russia to northern Vietnam.

Diet: Feed on aquatic plants but can also consume detritus, insects, small fish, earthworms and other invertebrates.

Life span: 5-11 years

Size: Maximum of more than 80 pounds and nearly 5 feet in length.

Did you know?

Grass carp can only digest about half of the plant matter it consumes each day. It expels the rest into the water, which enriches it and promotes the proliferation of algae.

In a day, they can consume up to 40% of its body weight in food.

Learn about the other species