The aquatic environment is the complex web of interconnected water, sediment, and biota that allows humans to survive. The buildup of harmful inorganic and organic contaminants in aquatic habitats could degrade them, which could have far-reaching negative effects on human health. When it comes to harmful contaminants, pesticides rank high. It is common practice to use pesticides in order to keep insects out of crops grown for human consumption and to clear homes and yards of disease-carrying animals such as rats, mice, ticks, and mosquitoes. Organic insecticides have replaced their synthetic counterparts due to the popular belief that they are safer for both humans and the environment. Despite coming from natural sources, these compounds can have major and frequently irreversible effects on aquatic ecosystems, according to recent studies. This chapter explores the intricate relationships between organic pesticides and aquatic life in order to better understand the immediate consequences of these chemicals on water bodies. Among the most precious natural resources are fisheries and aquatic resources, which encompass all bodies of water such as lakes, ponds, rivers, streams, and oceans. Along with the acknowledgment of aquatic systems and fisheries has come a growing concern over how a growing human population and their activities would impact the aquatic environment. As a major group of harmful compounds to which humans are exposed, pesticides have a deleterious effect on aquatic ecosystems.