The aims of the present study were to investigate the characteristic of the specific dynamic action (SDA) and the interaction between feeding and locomotive metabolism in goldfish (Carassius auratus). Firstly, goldfish was force-fed with 4% body mass of either compound feed or cellulose and the pre-feeding and postprandial oxygen consumption rate (Vo2) were measured to identify the characteristic of SDA. Then, the critical swimming speed (Ucrit) and swimming metabolic rate (MO2) at different swimming speed of fasting and fed fish were measured to identify the effect of digestion on locomotive metabolism. Lastly, the postprandial metabolisms of fasting or digesting fish swum under either 70% or 0% Ucrit were measured, aiming to identify the effect of swimming on feeding metabolism. The effect of locomotive on feeding metabolism and the effect of force-feeding with compound feed or cellulose on SDA were determined by paired t-test, whereas the effect of experiment treatments on active metabolic rate was determined by t-test. Effects of experimental treatment, swimming speed and (or) sample time on Ucrit or MO2 were determined by a analysis of variance (ANOVA) which followed by Duncan multiple-comparison posthoc test if it was necessary. The results showed that the SDA increase shortly after force-feeding of compound feed which lasted about 7 h while force-feeding of cellulose elicited no significant change in MO2 (Fig 1), suggesting mechanical SDA contributes little to SDA magnitude while biochemical SDA is the main components of SDA in gold fish. Ucrit decreased significantly while swimming MO2 increased significantly at any given swimming speed in fed fish compared with those of fasting fish. However, neither duration nor increment of SDA showed any significant difference between resting and swimming fish (70% Ucrit). The duration calculated as the time from feeding to when the metabolic rate returned to within the standard error of the resting metabolic rate of a given fish were both 6.5 h, and the feeding metabolism at any given sample time showed no significant difference (Fig 4). The present study demonstrates clearly that in goldfish, digestion shows profound negative effect on locomotive metabolism while locomotion shows little effect on feeding metabolism.