Significant amount of residual mercury was reported in bigger fish when compared to smaller fish. Mercury was not traceable in some fish collected from the contaminated estuary. Non availability of mercury in the area might be due to change in technology or washing of all discharged mercury into Bay of Bengal or a significant amount of mercury was recovered and recycled by following recycling technology. The effluent of the effluent canal showed an insignificant amount of mercury. In contrast the estuarine fishes showed significant amount of mercury in their body tissues. Aged fishes accumulated more and in case of smaller fishes no residue of mercury was found in brain, liver and muscle. Higher amount of mercury was recorded in all liver tissues of the contaminated fish followed by whole body, muscle and brain. Brain tissues showed the lowest amount of mercury. Tissue slice respiration of liver tissues of the contaminated fish was highly affected when compared to brain and muscle tissue slices of the contaminated fish. The obtained data was compared with respective control values. The depletion of tissue slice respiration was due to residual accumulation of mercury in different tissues of the contaminated fish.