Daily feeding rate in relation to temperature and diel feeding rhythm of the grey sea chub Kyphosus bigibbus were examined for Eisenia bicyclis and Sargassum patens forming seaweed beds under tank-rearing condition. Daily feeding rate of K. bigibbus ranged from 0.7 to 1.3% for E. bicyclis and from 3.4 to 4.6% for S. patens (in the temperature range from 20 to 30 ℃) and the fish showed almost no feeding at 12 ℃. K. bigibbus constantly fed on algae at night as well as in the daytime and in particular showed the most intensive feeding activity before sunset and after sunrise.