The routine metabolism of Hoplias m. malabaricus in relation to weight, at 3 different experimental temperatures (15, 20, 30ºC), through oxygen consumption in confinement and in the absence of external stimuli was studied. The metabolic index (mg O2/g.h) and the intensity of metabolism (mg O2/g.h), for each temperature, were obtained. An oxycalorific coefficient to convert milligrams of oxygen consumed into calories of liberated energy was used.