This study aimed to find suitable salinities for growth and their effects on the activities of digestive enzymes such as -amylase, pepsine and chymotrysine of snakehead (Channa striata) fingerlings. Snakehead fingerlings (sizing 7-9 g each) were exposed to salinities of 0, 3, 6, 9 and 12 for 90 days in order to observe growth, survival and feed conversion ratio (FCR). Similar experiment was also conducted to exam the activities of digestive enzymes in stomach and intestine of fish at the points of 3, 7, 14, 28, 56 and 84 days.

The results showed that the daily weight gain of snakehead after 90 days at 6 was highest (2.22±0.02 g/day) and at 12 was lowest (0.05±0.02 g/day). The activities of -amylase increased with the increase of salinity from 0 to 12. However, the activities of pepsine at 6 (6.28 mU/mL/mg protein) was significant higher if compared to that at freshwater or 0 (3.46±0.12 mU/mL/mg protein). The activity of chymotrypsine in freshwater increased during the experimental period. In brackishwater, the activity of chymotrypsine decreased as salinity increased from 3 to 12. The survival rate of the fish was highest at 6 (77.0±12.8%), however the significant difference was not found among treatments of 0, 3, 6 and 9. The lowest survival rate was found at treatment of 12. This study propose that the snakehead can be raised in the salinity water from 0 to 6.