The Shatt al-Arab River in Iraq has seen a significant spread and subsequent disappearance of certain shrimp species, potentially due to historical fluctuations in temperature and salinity. This study examines the effects of combined temperature and salinity on the oxygen consumption, metabolic rate, and thermal coefficient of juvenile Metapenaeus affinis. Salinity tolerance tests revealed that shrimp survived transfers up to 15ppt but experienced over 50% mortality at 20 ppt, with the highest survival (100%) at 5ppt and the lowest (17%) at 20ppt. Oxygen consumption increased with salinity at 20-21°C, with peak rates at 15 ppt (0.036mg O₂/h) and lowest at 1ppt (0.006mg O₂/h). At 25-26°C, oxygen consumption was higher at 10 and 15 ppt (0.040mg O₂/h) and lower at 5 and 10 ppt (0.010mg O₂/h). At 29-30°C, the highest consumption rate was 0.046mg O₂/h at 1ppt, while the lowest was 0.016 mg O₂/h at the same salinity in the second and third hours. Temperature significantly affected oxygen consumption, with the highest rate (0.018mg O₂/h) at 29-30°C and 15ppt, and the lowest rate (0.006mg O₂/h) at 20-21°C and 1 ppt. Metabolic rates peaked at 0.072 mg O₂/g at 29-30°C and 15 ppt and were lowest at 0.024mg O₂/g at 20-21°C and 1 ppt. These findings provide valuable insights for aquaculturists in developing practices to enhance growth and survival in varying environmental conditions.