Increasing the O. niloticus standing biomass reduced the SGR (Fig. 2) of B. gonionotus,
whereas increasing the C. carpio standing biomass had no negative effect on the SGR of
B. gonionotus (Fig. 3), indicating that there is an interspecific competition with O.
niloticus but not with C. carpio. This is in agreement with the findings of Haroon et al.
(1992) who found that the daily growth rate of B. gonionotus lowered when raised in
polyculture with O. niloticus