Fish were manually fed to apparent satiation twice per day at 08:00 and 16:00 h. Daily feed intake and fish mortality were recorded. A photoperiod of 12L:12D was maintained throughout the trial. A partial seawater exchange (30% total system volume) was performed once each week. Water quality parameters were monitored daily with a portable multi-meter (Pro 2030, YSI Inc., USA) and maintained at the following averages: temperature 24.8 ± 0.7 °C, dissolved oxygen 6.6 ± 0.3 mg L− 1, salinity 34.0 ± 0.5 ppt. The water pH (7.7 ± 0.2) and total ammonia nitrogen (0.3 ± 0.2 mg L− 1) were measured three times per week with a colorimeter (DR/890, Hach, USA).