The present study is carried out for the assessment of oxidative stress induced by fluoride which in aquatic ecosystems like other pollutants. Study has been carried out in cat fish (Heteropneustis fossilis) for investigation of definite biomarkers in kidney. Biomarkers selected for stress monitoring were malondialdehyde (MDA), an index of lipid peroxidation and antioxidant defence system enzymes, mainly reduced glutathione (GSH), Superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidise (GPx), Gluthione S transferase (GST) and Protein activities. Fish were exposed to 35 mg F /L and 70 mg F/L of water for 45 & 90 days. After experiment kidney was collected; a control experiment was also run for comparison .There was decrease activity of GSH, SOD, CAT, GPx and Protein in kidney tissues and increase activity of LPO and GST. Histopatholgical study of kidney revealed renal degeneration and hypertrophy of renal tubules epithelial cells and dilation in the glomeruli. These observations indicate that sub chronic exposure to the fluoride is capable of inducing oxidative stress in fish.
