Channa punctatus was exposed for 7days to sumithion at a concentration of 2.0, 5.0, 5.5, 10.0, 10.5, 15.0, 15.5, 18.5, 20.0, 20.5, 25.5 and 100ppm under laboratory conditions. The fish showed severe histological changes in liver, kidney and ovary tissues. The degenerative changes included hypertrophy of cells and their nuclei, liver cord disarray, vacuolation of the cytoplasm and necrosis. In some cells the membrane was ruptured. The liver on the whole showed distance appearance. Pycnosis, vacuolation, rupture of blood vessels and hematopoietic cells of kidney, fragmentation of ova were recorded in an increasing order towards the higher tested doses.
