Pollution is one of the major environmental problems which deteriorate the natural environment nowadays and their characteristic features are harmful for the human life and desirable species as well. The heavy metals like Lead and Nickel are the essential elements that may biaccumulate to toxic level, especially in the fishes. These elements creates the majority toxicity symptoms in larval stage, tertogenic and other deformaties in the living beings. There is a paucity of information available on the physiological stress response so an attempt has been made to evaluate such parameters with the heavy metals like Lead and Nickel for the investigation in fresh water fish species, O. niloticus and C. carpio (Mean weight 65.5±1.00 gm and mean length 10.0 ± 1.5cm) and (Mean weight 85.5± 1.00 gm and mean length 14.7± 1.20 cm). The 96h Lc50 for both species was computed as 14.35 mg/L (O. niloticus) and 16.75mg/L (C. carpio). These fishes later treated with sub-lethal concentration of (2, 4, 6 and 8 mg/L) and (3, 6, 9 and 12 mg/L) respectively and their liver and muscle were treated for total glycogen content in which a significant (P≤ 0.01) depletion was recorded. All the variations in the parameters are dose dependent and are in parenthesis. The depletion was more obvious in muscle than in the liver.
