Heavy metal pollution in aquatic ecosystems is a major environmental concern as these can accumulate in tissues and biomagnify the food chain interfering with the health and reproduction of fish. Fishes are sensitive indicators of pollutants present in the water. Heavy metal salts constitute a serious type of pollution of aquatic biota, because they are stable compounds. Tolerance to stress is likely to be lower in the reproductive tract than in any other organ system in fish. The fresh water gobiid fish Glossogobius giuris was exposed to sub lethal concentrations of heavy metals (Copper sulphate, 0.3 and 0.5ppm; Cadmium sulphate, 0.02 and 0.04ppm) for short term (24 to 96 hours) duration to understand the reproductive modulations. The effects of heavy metals on the seminal vesicles include vesicular regression, degenerating secretory cells and locules with minimal quantity of vesicular fluid and necrotic sperms. The study suggests that depletion of sperms in the seminal vesicle due to heavy metals alters the structure of the seminal vesicle, affects sperm motility and in turn the reproductive potential of the fish
