In much of the developing world, the high cost of purchased feeds makes meat and milk too expensive to be consumed by the producers' own families. A fish pond integrated with livestock or crop production provides an important source of animal protein for home consumption or sale. This protein involves almost no cash costs, since the needed nutrients and energy are supplied by crop residues, green manure, livestock manure and sunlight. Conversion of manure into animal flesh is possible because the anoxic sediments support a microbial flora similar to that of the rumen. Although integrated fish farming has been practiced for thousands of years in China, it has not yet been successfully adapted to all regions for which it potentially is applicable. A program in Wuxi, China brings together students and scientists from all over the world who are working towards that goal.