Polyculture is the practice of raising a few selected species of fish in proper arrangements in a pond to maximize total fish production (composite fish-farming).
Fast-growing suitable fish species with various feeding patterns are selected and seeded together in this manner.
The culture of a mix of Chinese carp (silver carp), grass carp, and bighead carp is a good illustration of this strategy.
Phytoplankton is consumed by this Chinese carp, pond vegetation is consumed by grass carp, and zooplankton is consumed by bighead carp. As a result, the pond's available food is better used, resulting in increased productivity.