The researchers studied how different amounts of supplementary feeds affect the growth and production of fish in ponds with multiple species. They used rice bran and wheat bran as feeds in different quantities, along with fertilizers. The ponds were monitored for various factors like water quality and plankton levels. The results showed that ponds with higher feed amounts had significantly more fish production compared to those with lower or no supplementary feeds. This suggests that using supplementary feeds along with fertilizers can greatly improve fish growth in polyculture systems.