Giant gourami (Osphronemus goramy) with an initial weight of 10.4±0.04 g fish-1 were used
for two experiments. In the first experiment, 500 L tanks with 50 fish in each tank were exposed to
different temperatures (22, 25, 28, 31, and 34°C) for 56 days. The stomachs and intestines of the fish
were collected at 14, 28, and 56 days to determine the activities of the digestive enzymes such as
trypsin, chymotrypsin, and α-amylase. In addition, plasma glucose concentrations were measured at
these sampling times. The second experiment was conducted at the same temperature levels and the
fish were reared for 90 days to determine survival rate, growth, and food conversion ratio. The results of
the study showed that digestive enzyme activity (trypsin, chymotrypsin, and α-amylase) increased as
the temperature increased from 22°C to 31°C. After 90 days, the highest daily weight gains and specific
growth rates of the fish were 0.68±0.01 g day-1 and 2.24±0.03 % day-1, respectively at 31°C, while the
lowest were found at 22°C (0.13±0.01 g day-1 and 0.88±0.09 % day-1, respectively). Therefore,
temperature significantly affected the digestive enzymatic activities and growth performance of
fingerling-sized O. goramy.