Due to Cadmium pollution, Cd enters into all the food chains including animal human food chain via air, water, soil, and food contamination. Cadmium is highly toxic beyond its permissible limits of exposure and has acute and chronic effects on aquatic animal as well as terrestrial animals including human beings and environment. The present investigation was undertaken to evaluate Cd toxicity, LC₅₀ and its impact on growth & the various biochemical parameters like glycogen, glucose, protein, lipid and amino acid content in nine different tissues of exposed catfish (Clarias batrachus) in laboratory conditions for 14 days to sub lethal and lethal concentrations of Cd. First, the acute toxicity experiment was conducted to evaluate LC₅₀ of Cadmium chloride (CdCl₂) on Clarias batrachus which was found to be 450 ppm for 96 hours. Clarias batrachus (average length of 8.5±0.5cm and average weight of 13.5±0.5g) was exposed to sub-lethal concentration (140 ppm) and lethal (450 ppm) concentrations of Cd for 14 days had been observed. All biochemical components were decreased in all the tissues except glucose which increased significantly in the lethal concentration. The growth of the control and Cd sub-lethal concentration treated catfish was nearly same, but retarded growth was observed in the lethal concentration of CdCl₂ treated fish. The sub-lethal concentration is host friendly. The exposed fish showed significant behavioural changes like rapid opercular movement and frequent gulping of air. The present result clearly indicate that the changes of these parameters due to lethal concentration of Cd may provide an early warning signal to us for their effects in fishes, aquatic animals, terrestrial animals and human beings by biomagnifications. Thus the discharge of effluents containing Cadmium into the water resources may be threats to aquatic fauna and flora as well as human beings.