
The aquatic medium such as pond, lake, estuary, water reservoirs and rivers surrounding the industrial, agricultural fields and urban areas in India, pose a serious risk for survival of aquatic organisms due to water quality deterioration through industrial effluents, excessive nutrient inputs, acidification, heavy metal, fertilizer contamination and organic pollution. Chromium is known to be a very toxic pollutant introduced into natural waters from a variety of sources including industrial effluents. The aim of the present study is to assess the protein and amino acid content in brain and muscle of the fish Oreochromis mossambicus exposed to sublethal concentrations of heavy metal chromium 1/10th (high), 1/15th (medium) and 1/20th (low) of the 96 hour LC50 values for the period of 10, 20 and 30 days. The fish exposed to chromium showed a decrease the glycogen levels in kidney, brain and muscle for 10, 20 and 30 days. However, no information is on record concerning the three different sublethal concentration of heavy metal chromium on the glycogen levels of fish. The objective of the present work was to assess the effect of heavy metal chromium on glycogen levels in kidney, brain and muscle of freshwater fish, Oreochromis mossambicus.