InPuntius sarana, changes in metabolic rates in relation to ambient oxygen fell into the general pattern at 30 and 55° C, the differences being mainly in the levels of metabolism, both aerobic and anaerobic. The mean RQs at high ambient oxygen were 0.77 and 0.63 revealing that the fish were aerobic under adequate ambient oxygen. The hypoxic RQ were 1.42 and 1.90 suggesting that the fish derived considerable energy anaerobically. The aerobic AQs ranged between 0.06 and 0.18 depending on the utilization of protein and the hypoxic AQs were in consonance with the corresponding changes in hypoxic RQs. As judged from the asphyxiai oxygen level,P. sarana can live, below air saturation, up to 0.41 and 0.49 mg O2/1 at 30° and 35°C respectively. The random activity of the fish increased with decrease of ambient oxygen.