This study was carried out in an agricultural, industrial, domestic, and slaughterhouse area that is also a discharging region of the river Ceyhan just under the crest of the Aslantas dam. Levels of pollution indicator parameters of the water were observed and their effects on various oxidative stress biomarkers in gill and liver tissues of spotted barb (Capoeta barroisi Lortet, 1894) were investigated. The oxidative stress biomarkers analyzed included superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PD). Levels of reduced glutathione (GSH) and lipid peroxidation (LPO) were also evaluated. High levels of CAT, G6PD, GST and GSH activity were found in the liver tissues of fish collected from the river Ceyhan discharging region; it was determined that the region was polluted. Substantially high levels of SOD and LPO (P < 0.05 in gill and liver) were observed.