ABSTRACT
Presence of mercury and other heavy metals above permissible levels in water bodies across the globe is posing a serious threat to aquatic biota and public health. Occurrence of mercury above the permissible limits in the aquatic ecosystem of Hyderabad city is well established. In this context, we carried out static- renewal bioassays on the zebra fish, Danio rerio exposed to different concentrations of mercuric chloride, and the 96-h median lethal concentration (LC50) was found to be 0.077 mgl-1. Behavioral manifestations like loss of scales, hyper secretion of mucus, surfacing and darting movements, loss of balance, irregular swimming patterns were noticed in the fish exposed to 0.077 mgl-1. The present study also examined the toxic effects of mercuric chloride on vital biochemical constituent’s total glycogen and total protein. Significant decrease (p<0.001) in glycogen and protein content of fish exposed to 0.077 mgl-1