an addendum to an earlier message:
>Polyculture is practiced in brackish culture and mariculture in China. Although
>it is incompatible to stock plankton feeders with carnivorous fish species, a
>few predators can keep over population of tilapia. It is a mixed farming by
>using prey predator relationship. In a broad sense, it is also called polyculture.

The fish species stocked into a fishpond for polyculture should be
compatible or complementary so as to fully utilize all the ecological
niches in water body. For example, we have silver carp, bighead carp,
grass carp, black carp, bream, common carp, crucian carp and now Tilapia
stocked into the same pond for polyculture in China. They are all compatible.

Best regards
Li Kangmin.