This study investigated the carbohydrate reserves and metal accumulation of the Nile tilapia, Oreochromis niloticus after exposure to sublethal concentrations of heavy metals such as copper, lead and zinc for a 12-week period, using static renewable toxicity tests. The concentrations of the metals accumulated in the tissue of exposed fish were about 3-5 times higher than the concentrations detected in control fish. The accumulation of plasma glucose in O. niloticus was observed to be dose dependent. It is significantly higher (P