Histological teration in the gill tissues of Cyprinus carpio and Carassius auratus fishes after exposure to sublethal concentrations of malathion insecticide

This study aimed at evaluation the effect of malathion insecticide upon Cyprinus carpio and Carassius auratus . The study revealed that gills of fishes were infected after 16 days of exposure to sub lethal concentration in the range 0.01 - 0.05 mg/1 of malathion insecticide. Fishes which exposed to different concentrations of the insecticide were characterized by randomly circular movement and an increased in the movements of operculum, enlargement of eye ball, increase in the excrement of mucus material and the fish come close to the aeration source and water surface. As time passed the fish color changes and the pectoral fin became wider. During the death hours the fish turned over on both sides close to water surface and after death a bad smell released.