Effect of meal sizes (0%,1%,2%,4% and 8% body mass) on postprandial metabolic response was investigated in juvenile Darkbarbel Catfish (Pelteobagrus vachelli) (7.03±0.15 g,n=42) at 25±0.5℃.Fish were lightly anaesthetized and force-fed with freshly killed loach.The postprandial metabolic rate firstly increased and then slowly decreased to pre-fed level.The SDA duration were 8,24,26 and 36 h and time to peak metabolic rate (PMR) were 4,4,6 and 6 h in 1%,2%,4% and 8 % meal size groups.The peak metabolic rates of 8% meal size (97.25 mg O₂/kg·h) and 4% meal size (87.46 mg O₂/kg·h) groups were significantly higher than that of 2% meal size group (70.37 mg O₂/kg·h),while the latter is significantly higher than that of 1% meal size group (56.08 mg O₂/kg·h) (P<0.05).The energy expended on SDA increased with meal size while the SDA coefficient of 1% meal size group was significantly lower than those of other meal size groups (P<0.05).The maximum exercise metabolic rate (MMR,166.5 mg O₂/kg·h) was significantly higher than PMR (P<0.05).Both PMR and duration increased to fulfill the increased energy expenditure during SDA with the increasion of meal size.The similar trapeziform postprandial metabolic profiles of 4% and 8% meal size groups suggested that the increasion of PMR is restrained at high meal size range.The lower value of PMR/RMR implied that Darkbarbel Catfish has low feeding metabolic capacity.The withholding of large metabolic scope for locomotion and other physiological activities might be related to its active foraging mode.