(species Cyprinus carpio), hardy, greenish brown fish of the family Cyprinidae. It is native to Asia but has been introduced into Europe, North America, and elsewhere. A large-scaled fish with two barbels on each side of its upper jaw, the carp lives alone or in small schools in quiet, weedy, mud-bottomed ponds, lakes, and rivers. It is omnivorous, and in rooting about for food it often roils the water, increasing turbidity and adversely affecting many plants and animals. As a result, it is often considered undesirable, and much effort may be devoted to its extermination.

In winter the carp becomes torpid, retires to the bottom, and stops feeding. It usually spawns in spring, when the female deposits numerous eggs on plants or detritus, usually in shallow water. The eggs hatch four to eight days later. Carp grow rapidly, attain sexual maturity about the third year, and in captivity may live more than 40 years. They average about 35 cm (14 inches) in length but may grow to more than 100 cm and 22 kg (49 pounds).

The carp is often raised for food, especially in Europe and Asia, because it is possible to produce large amounts of fish per acre. Two domesticated varieties of the species are the mirror carp (with a few large scales) and the leather carp (almost scaleless). The crucian carp (Carassius carassius) is a barbel-less European relative of the goldfish. The grass carp (Ctenopharyngodon idella) is an Asian species that has been introduced into North America.