A detailed study was carried out to evaluate the suitability of biofloc system condition for cultivation of Keeled mullet (Liza carinata) fish. The experimental design consisted of 2x2 factors experimental arrangement of two levels of crude
protein (23 and 28% CP) and two culture systems (clear water system (CWS) change and biofloc treatment (BFT) with zero water exchange): (CWS23%, CWS28%, BFT23% and BFT28%), where the superscripts refer to the levels of crude protein. Each treatment included three glass aquaria (80 X 45 X 30 cm) and stocked by 15 fry per
aquarium with an average initial body weight of 0.26±0.003g. Total weight gain (TWG), average daily gain (ADG), and specific growth rate (SGR) were determined. Fish fed on 28% CP had significantly higher values of FBW, FI, FCR, EG and ER (24.41, 25.81, 1.06, 34.20 and 20.68, respectively) compared with values for fish fed on23% CP (17.91, 1.19, 27.38 and 17.86, respectively). Fish fed on 23% CP had significantly higher PER and PPV values (3.83 and 72.91, respectively). Fish reared under CWS had significantly higher FI, FCR and ER (28.36, 1.38 and 20.22, respectively), while fish reared under BFT had significantly higher PER, EG and PPV values (4.57, 31.62 and 87.40, respectively). The highest amount of feed intake was recorded by CWS28% (33.94). CWS 28%treatment had significantly highest FBW
(25.45) value, while CWS 23% treatment had the lowest FBW (16.40). Fish reared under biofloc treatment recorded the highestΣω3 levels in their whole bodies compared to that reared under (CWS) clear water system. It could be concluded that biofloc technology is a suitable system for Liza carinata cultivation economically and environmentally.