We evaluated the effects of salinity and alkalinity on growth, feeding, and gill microstructure in juvenile (control group), 2.0, 4.0, 6.1, 7.8, 10.0, or 11.9 for 60 d with temperature of 22. The body length, body weight, and specific growth rate (SGR) of juveniles were significantly lower in fish held at salinities <6.1 than in those held in salinity >6.1(<0.05). The maximum final body weight was highest in the fish reared at 2.0. The specific growth rate of weight (SGRW) and feed conversion efficiency (FCE) were highest in fish held at 4.0 and lowest in fish held at 11.9. Our results suggest the optimal salinity for growth is 1.88, whereas exposure to levels 7.8 results in negative effects. Fish were also reared at 10.00, 15.83, 25.10, 39.80, and 63.12 mmol/L NaHCO₃. The body weight, length, and the SGR of juveniles reared in water with <25.10 mmol/L NaHCO₃were significantly lower than in the remaining groups (0.05). The largest final body weight, body length, SGR, SGRW, and FCE were in fish reared at 15.83 mmol/L NaHCO₃.The fish reared at 63.12 mmol/L NaHCO₃ had the lowest values for all indices. Rearing in water with NaHCO₃ levels >39.80 mmol/L had negative effects and the optimal alkalinity for growth was 20.57 mmol/L. Observation of gill microstructure revealed hypertrophy in the chloride cells, and both hypertrophy and edema in the epithelial cells as salinity and alkalinity levels increased, thereby affecting the growth of the fish. In conclusion, the salinity should bebelow 6.1 or the alkalinity should be below 25.10 mmol/L in the larvae culture.