The effects of rearing temperature on white muscle and hepatic phosphofructokinase(PFK),pyruvate kinase(PK),lactate dehydrogenase(LDH),aspartate aminotransferase(AST) and alanine aminotransferase(ALT) were examined in fingerlings of blue tilapia,O reochromis aureus. The experiment was conducted for 14 weeks at temperatures of 18,22,26,30,and 34°C. The activity of the glycolytic enzymes PFK,PK,and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver,except for LDH,which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization,while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature. The effects of rearing temperature on white muscle and hepatic phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were examined in fingerlings of blue tilapia, O reochromis aureus. The activity was conducted for 14 weeks at temperatures of 18, 22, 26, 30, and 34 ° C. The activity of the glycolytic enzymes PFK, PK, and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver, except for LDH, which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization, while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature.