Aquatic Toxicology is the study of the consequences of environmental pollutants on aquatic organisms, like pesticides especially insecticides, Pesticides are highly toxic not only to fish but also to other organisms, the more acute toxicity are insecticides. Since fishes are important sources of proteins and lipids for humans and stock, that the health of fishes is very important for citizenery. Insecticides are the chemicals accustomed control insects by killing or preventing them from engaging in undesirable behaviors or destructive. Application of insecticides used to control a wide variety of insectivorous and herbaceous pests which might otherwise diminish the number and quality of food productions. The insecticides, are threatening the long-term survival of major ecosystems by disruption of ecological relationships between organisms and loss of biodiversity. The key Chemical groups of insecticides that are usually applied are Organophosphate, Carbamates, Organochlorine, Pyrethroids, and Necotenoides.