A field study was conducted to assess the effect of mono- and polyculture systems in net Hapas of monosex Nile tilapia (Oreochromis niloticus), striped mullet (Mugil cephalus) and /or thin-lipped mullet (M. capito) at different stocking ratios on growth performance, feed efficiency, chemical composition of the whole body, and economic efficiency parameters of experimental fish for 107 days rearing period. Five experimental treatments were represented as 100% Nile tilapia (T₁, monoculture); 75% Nile tilapia: 25% striped mullet (T₂, polyculture); 75% Nile tilapia: 13% striped mullet: 12% thin-lipped mullet (T₃, polyculture); 50% Nile tilapia: 50% striped mullet (T₄, polyculture) and 100% striped mullet (T₅, monoculture). Fish ofT₂ showed the highest significant of all growth performance, feed utilization, and economic efficiency parameters followed by the same fish species reared in polyculture system (T₄) at stocking ratio (50%: 50%) compared to other experimental fish-culture systems. Generally, it could be recommended that rearing monosex O. niloticus in polyculture system with M. cephalus at stocking ratio 75%: 25%, respectively (T₂) is more effective than other aquaculture systems under the experimental conditions of the present study.