Effect of mercuric chloride on gill structure of a freshwater fish Oreochromis mossambicus (BLOCH)

Fresh water fishes are economically important and an alternative source of significant human dietary constituents. The experimental fishes treated with lethal concentrations (1.00, 1.50, 0.63 and 2.00 ppm) of mercuric chloride showed many histological changes during 1 to 4 days of exposure. The gills showed vacuolization in the gill stem, gill lamellae ruptured, connective tissue cells in the stem damaged, destructed and congestion of haemocytes in the gill lamellae are observed. The present work on histological observation was carried out to know lesions in gills that had resulted from lethal exposure of the freshwater fish O. mossambicus to mercuric chloride.