Rice, fish, and the planet – in south China for over 1200y, farmers have grown an indigenous species of common carp in their rice paddies. The carp eat insects and weeds

It's a literature review largely based on DOI:10.2307/23060037 which "found that RF [rice-fish] maintained the same rice yield and stability as RM [rice monoculture] but required 68% less pesticide and 24% less chemical fertilizer" and "confirmed that the temporal stability of rice yield is higher in RF than in RM in the absence of pesticide"