Grass Carp - Ctenopharyngodon idella

Also known as: Amur, White Amur

The grass carp is a fish that is native to rivers of China and Eastern Siberia (the Amur River system) that flow into the Pacific Ocean. They have been widely introduced around the world for aquatic weed control and aquaculture purposes. Because of the potential negative impact of the fast-reproducing grass carp on other, more popular sport fish, sterile (triploid) grass carp were developed for release into wild ecosystems. To ensure the fish are sterile, fertilized eggs are shocked with hot or cold water or with pressure, causing them to retain an extra set of chromosomes. They are called triploid carp because they have three sets of chromosomes instead of the normal set of two. The aquatic weed control capabilities of the non-reproductive triploid grass carp appear to be essentially the same as the naturally reproducing carp. In the United States, naturally reproducing, non-triploid populations are reported around Mississippi River Basin.

The mullet-shaped head with a terminal mouth and no barbel, and coarse dark-edged scales are distinctive features of the grass carp. The dorsal fin, with 8 rays, is short and located at mid-body, above the pelvic fins. Paired anal fins are short and attached low on the body. The coloration is typically olive green to silvery white.

While grass carp might be reluctant to bite, once hooked they are strong fish that put up a tenacious fight and are known to jump. Being an herbivorous fish, the most popular methods of targeting grass carp include still fishing with dough balls but fly fishing for this species is becoming increasingly popular. In some countries grass carp are an integral part of fish culture and form an important source of fish protein for human consumption but this fish is not a popular eating fish in the United States.