Supplementary fish - are added to the main object of breeding in ponds, lakes for a more complete use of forage resources of ponds and increase the yield of fish per unit area.

For example, in warm-water carp farms, silver carp, whitefish, vendace, rainbow trout, orpha, tench, sterlet and other fish are grown as supplementary fish. The use of supplementary fish makes it possible to use the ponds' food base to the fullest extent. Planting of additional fish in the feeding carp ponds is calculated according to a special formula. Calculation of mixed planting depends both on biological features of the feeding pond and on nature of feeding of different age groups of fish in different time intervals of vegetation period.