The objective of this study was to investigate the effect of different water salinities on juvenile Hoplias lacerdae during feed training. Salinity levels of 0, 3, 6 and 9 g salt L -1 were used. Juveniles (3.33±0.1 cm and 0.6±0.09 g) were stocked at a density of six fish L -1 in aquaria (10 L volume) with supplementary aeration. Weight gain, length gain, and rates of survival, mortality, and cannibalism were evaluated after 20 days. Total mortality was observed in 0 g of salt L -1 . The best

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... vival rates of 98.7 and 97.5% were recorded in 3 and 6 g of salt L -1 , respectively. The greatest weight gain was recorded in fish grown in 3 g of salt L -1 followed by fish grown in 6 g of salt L -1 . Length gain was similar in the 3 and 6 g salt L -1 groups. No weight or length gain was recorded in 9 g of salt L -1 . According to regression equations, the optimum water salinity was 5.15, 4.03 and 4.55 g of salt L -1 for survival rate, weight, and length gain, respectively. Salinity between 4.03 and 5.15 g of salt L -1 during feed training of juvenile giant trahira improves productive performance.