The fish were housed in several 100 L tanks for 5 d at 26°C and were fed on the same commercial pellet used in the hatcheries. After feeding on pellets and defecating, the fish were separated into four identical experimental tanks, with each tank (350 × 170 × 125 cm) with two compartments (15 fish in each compartment). The compartments were separated by a plexiglass with holes to ensure similar water temperature across the tank. The fish in two compartments were fed twice daily (Rimmer 1998) at 9:00 and 16:00 h at a rate of 10% of body mass per day on commercial pellet (Star feed: Marine 9982/84, CP Group, Malaysia: 50% protein and 8% lipid) and on freshly thawed shrimps (Acetes sp. 58% protein and 8% lipid, Manivannan et al. 2010). The uneaten food was siphoned from the tanks