Fish samples were collected at Wadi Hanefah (WH) and in an unpolluted commercial fish farm designated as the control site (CS). Several antioxidants (superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and glutathione (GSH)) and the oxidant malondialdehyde (MDA) were selected as bioindicators, and their concentrations were assessed in Poecilia latipinna from WH and CS. SOD activity was increased by 52.8% in the kidney, 61.3% in the liver and 18.2% in the heart of P. latipinna from WH, whereas a significant decrease (39.4%) was observed in the gills compared to the control fish, P. latipinna. In contrast, CAT activity was decreased by 33.2%, 49.2%, 52.1% and 56.2% in the gills, kidney, heart and liver, respectively in P. latipinna from WH. GST activity was also increased in the kidney, heart and liver of P. latipinna from WH by 34.4%, 42.2% and 54%. However, GST activity was decreased (55%) in the gills of fish from WH compared to the fish from CS. GSH concentrations were increased by 44.8%, 35.3% and 32.7% in the kidney, heart and liver but were decreased by 33.6% in the gills. MDA levels in P. latipinna from WH were increased in the gills, kidney, heart and liver by 83.3%, 167.3%, 161.4% and 178.7%.