
Histopathological lesion have been studied in the liver of Mystus vittatus under 10, 20 and 30 days of exposure to 10% sub lethal concentration of monocrotophos (96 hr LC50 : 0.025 ppm; 10% SLC-0.0025 ppm). In control cat fish, the liver was comprised of polygonal hepatocytes with centrally placed nucleus. Pesticide induced dilation of blood sinusoids, vacuolization and disintegration of cell boundaries were noticed in the 10 and 20 days of exposed fish. The complete damage of hepatocytes and loss of integrity of cell wall were noticed on 30 day of exposure.