Diur nal change of standard metabolism and specific dynamic action of Ctenopharyngodon idel la (body we ight in 15 -20g)wer e measured .The mean rate of standard metabolism and me tabol ic energy were 114mgO2/kg·h and 50 .16kJ/kg·d at 20 ℃ respect ively.Heat increment was 38 .64kJ/kg·d which was 10 .09 % of intake energy . Ener gy of standard me tabol ism and heat increment at 28 ℃were 1 .4 and 1 .3 t imes as much as those at 20 ℃.