Two experiments were executed to investigate the correlation among water temperature, metabolic rate and swimming behavior of red sea bream Pagrus major. In the former experiment, the relationship between oxygen consumption and water temperature was measured in laboratory respirometry trials.The result showed water temperature (T, °C) has the following correlation with oxygen consumption (OC, mg min.−1kg−1); OC=1.47+0.01×1.22T, R=0.92. In the latter experiment, a wild adult fish was tracked in the open sea using an ultrasonic transmitter to record the horizontal migration paths, vertical swimming trajectory and ambient water temperature. The fish rested on the bottom during the day. While at night, it swam up and down within the depth range 30 to 80 m. The ambient water temperature ranged from 18.5 to 22.9°C. In the period of resting, the red sea bream was estimated to consume oxygen ranging from 1.91 to 2.55mg min.−1kg−1, in the open ocean. During the experimental period of 28 days, the fish remained within a shoal and moved only small horizontal distances. Fluctuation of ambient water temperature seemed to have little effect on the swimming behavior of red sea bream.