The present study was carried out to investigate the effect of biofloc technology (BFT), feeding rate (FR) and dietary protein levels (PL) on growth performance, survival (%) ,feed utilization and economical evaluation parameters of Nile tilapia (Oreochromis niloticus) flathead grey mullet, (Mugil cephalus) and thin-lipped mullet, (Liza ramada) fingerlings. Two different daily feeding rate (FR^2%BW and FR^3%BW) and three dietary protein levels (PL^20%, PL^25% and PL^{30% CP}) under the conditions of regular water exchange system or zero water exchange using BFT (Biofloc technology) were studied. The 12 experimental treatments were studied in duplicate and were allocated in twenty four 16 m³ concrete ponds. Nile tilapia final body weight (FBW), total weight gain (TWG), average daily gain ( ADG), specific growth rate (SGR) (%/ day) and survival (%) were significantly affected by rearing system and feeding rate. Significant difference was observed for the effect of dietary protein level on growth performance of Nile tilapia. It could be concluded that BFT system enhanced survival and growth rates of tilapia and mullet ssp. in polyculture under low feeding levels (2%) and high protein diets (30% CP) regimes.