@zephzoid: Chinese farmers have been raising carp inside the rice paddy for over a thousand years, and the fish do the weeding. In Qingtian County, native Oujiang red carp go into flooded paddies and eat the weeds and insects a grower elsewhere would spray for, while their waste fertilizes the rice. The FAO named the system one of its first Globally Important Agricultural Heritage Systems in 2005. Rice growers and small fish farms near you are on Localize too. Sources: FAO