The black carp (Mylopharyngodon piceus) or Chinese black roach is a species of cyprinid freshwater fish and the sole extant species of the genus Mylopharyngodon. It is native to lakes and rivers in East Asia, ranging from the Amur Basin across China to Vietnam. One of the largest cyprinids in the world, the black carp has a typical length of , though it can reach up to in length and in weight. It is carnivorous and generally feeds on invertebrates such as snails, clams and mussels. Black carp, together with bighead carp, silver carp, and grass carp, make up the culturally important "four famous domestic fishes" used in polyculture in China for over a thousand years. It has also been introduced in the United States as one of the invasive "Asian carps", though it is not as widely distributed worldwide as the other three. In China, black carp is widely cultivated for food and Chinese medicine, being one of the most highly esteemed and expensive domestic food fish, and partly because of its diet and limited food supply, is the most scarce and expensive in the marketplace among the "four famous domestic fishes". Description Black carp are elongated fish with a fusiform body. They appear dusky gray, brown or bluish black and have dark fins. Their dorsal fin is high and pointed. In comparison to grass carp, the distances from the eye to the superior and inferior edges of the pre-operculum are respectively longer, contributing to the elongate appearance of the scaleless head. Unlike in grass carp, the upper lip does not appear to protrude beyond the lower lip when viewed from above with the fish's mouth closed. Black carp have large cycloid scales on their body and a forked tail fin behind a broad caudal peduncle. Black carp in the United States The black carp was first accidentally introduced into the United States during a grass carp shipment from Asia in the 1970s. The black carp was later intentionally introduced to the US in the 1980s for use in retention ponds and aquaculture facilities to manage yellow grub and snails populations. It was also to be used as food fish. However, flooding in the South caused these populations of carp to spread into the Mississippi watershed. They continued to spread via the Mississippi and Missouri Rivers, where they began to form wild populations. Black carp later began to migrate