Present research embodied effect of organotin tributyltin chloride on freshwater prawn, Macrobrachium kistnensis. In toxicity evaluation of organotin tributyltin chloride on Macrobrachium kistnensis is highly sensitive to TBTCl toxicity. In the present study the safe concentration was 0.0322 ppm. The respiratory changes in oxygen consumption in the prawn, Macrobrachium kistnensis after exposed to 48hours, 1/3rd and 1/10th lethal and sublethal concentrations for 2, 4, 8, 12 and 24 hours have also been studied. The death of freshwater prawn, Macrobrachium kistnensis might be due to the impact...