The Grass Carp is a herbivorous, freshwater fish species of family Cyprinidae, and the only species of the genus Ctenopharyngodon. It is cultivated in China for food but was introduced in Europe and the United States for aquatic weed control. It is a large cyprind native to Eastern Asia, with a native range from Northern Vietnam to the Amur River on the Siberia-China border. It is a fish of large, turbid rivers and associated floodplain lakes, with a wide degree of temperature tolerance. Grass carp are usually thought to enter reproductive condition and spawn at temperatures of 20 to 30 °C, but have been shown to sometimes spawn at temperatures as low as 15 °C.