To study the effects of different dietary carbohydrate levels on growth,glucose metabolism indicators and tolerance ability in fishes of different feeding habits after an 8-week feeding trial,this experiment was conducted taking Tilapia(GIFT, Oreochromis niloticus),Derbio(Trachinotus ovatus) and Cobia(Rachycentron canadum) as the research objects,dextrin as the sugar source,three levels of dietary carbohydrate for each fish at low,medium and high levels(C_L,C_M,C_H; Tilapia:20%,30%,40%; Derbio:13%,26%,39%; Cobia:12%,24%,36%) respectively.The results showed that:the different carbohydrate levels had no significant effect on survival rate of Tilapia(P>0.05); The feeding conversion rate(FCR) showed an increasing trend after the first decline with elevated levels of dietary carbohydrate and the C_L group in Tilapia was the highest(P<0.05); The weight gain rate(WGR) and specific growth rate(SGR) were all the highest in C_H group and significantly higher than the C_L group(P<0.05).The survival rate in C_H groups of Derbio and Cobia were significantly lower than the other groups(P<0.05).However,the WGR and SGR in C_M were the highest significantly(P<0.05).The FCR first increased,then decreased with dietary carbohydrate levels elevated and the C_M lowest groups were the lowest(Tilapia:1.47,Derbio:1.61,Cobia:1.49)。Different dietary carbohydrate levels have different effects on glucose metabolism indicators of fish.With rising levels of dietary carbohydrate in Tilapia,the plasma glucose,insulin,hepatic/muscle glycogen and triglycerides of C_H group were significantly higher than the other groups(P<0.05).The plasma glucose,insulin,hepatic/muscle glycogen,triglycerides of C_H groups in Derbio and Cobia are the highest,but there was no significant difference in plasma glucose and insulin between C_L and C_M groups in Derbio(P>0.05).There were also no significant differences in plasma glucose and insulin levels of C_M and C_H in Cobia(P>0.05).The glucose tolerance test(GTT) results showed that:(1) After injection of glucose,the plasma glucose levels of Derbio and Tilapia groups reached the peak at 1 h(P<0.05) and returned to the initial level at 12 h while the Cobia until 24 h after a peak at 3 h.(2) The plasma insulin levels in tilapia and cobia groups rose slowly after the injection of glucose and reached the highest level at 3 h(P<0.05),while the lever in Derbio group was significantly decreased within 1 h(P<0.05).(3) The glycogen levels in Derbio and Tilapia increased slowly and reached the peak at 3 h and 6 h respectively(P<0.05) while the Cobia declined within 1 h.(4) after the injection of glucose,The triglyceride levels in Tilapia and Derbio reached the peak at 3 h and 6 h after injection of glucose respectively(P<0.05) while the Cobia decreased significantly within 1 h(P<0.05).The results of this study suggest that dietary carbohydrate levels have varying degrees of effects on the growth,glucose metabolism indicators,glucose utilization and tolerance of three feeding habits,fish.The omnivorous Tilapia can utilize the dietary carbohydrate better than carnivorous fish.The glucose tolerance ability of omnivorous Tilapia is the strongest,followed by Derbio the intermediate,and Cobia the lowest.