ABSTRACT
Toxicological effects of some biochemical parameters of freshwater fish Channa punctatus (Bloch), under the stress of Nickel (NiSO4. 6H2O), at various concentrations of 10, 20, 30 and 40 ppm for 30 days were observed. Gradual decrease in the levels of liver protein and liver ascorbic acid due to proteolysis and liver glucose breakdown respectively was observed. Contradictorily, high liver cholesterol level, may be due to hepatic disfunctioning and accumulation in brain. There was also gradual decrease in the brain protein level showing significant alterations but the brain ascorbic acid level showed no significant alterations. Decrease in the protein and ascorbic acid level and increase of cholesterol level thus indicates stressful condition of the fish.