Heavy metal ecotoxicity has been recognized to be a major threat to aquatic organisms and there are several health risks associated with it.This in-depth review investigation explores the critical issue of heavy metals pollution, concentrating on the hazardous effects of chromium, cadmium, lead, mercury, and zinc oxide nano particles on aquatic species. The balance of nature suffers as industrialization, urbanization and unsustainable land use changes spreads throughout the earth, with heavy metals released by industries causing destruction on the environment. These contaminants build up in living things, damaging their metabolism, immunological system as well enzymatic functions. The significance of the global ecological problem is clear, particularly in developed nations with a significant concentration of businesses. The present review also provides an analysis of each heavy metal’s toxicity patterns, considering things like age, species, and abiotic circumstances. Moreover, research is also done on how heavy metals affect different organ systems, such as the brain, gills, liver, kidneys, and reproductive system of aquatic species. Histopathological abnormalities, oxidative stress in cells altered metabolism, and even endocrine disturbance are just a few of the reported alterations. The toxicological consequences of zinc oxide nano particles are also examined in the present review, emphasizing the possible harm they may do to many aquatic species. The present review also emphasizes the necessity of tackling this significant issue and advances our understanding of the damaging effects of toxic metals on aquatic environments.