Calculated the LC 50 value of Lead nitrate in the fresh water air breathing fish, Channa punctatus. To elucidate the changes in biochemical parameters like glucose, proteins and lipids.To understand the effects of lead nitrate on the fresh water air breathing fish Channa punctatus.The effect of heavy metals on aquatic organism is currently attracting wide spread attention particularly in studies related to industrial pollution.Hazardous nature of the high toxic industrial pollution affect large aquatic environment.Fishes live in very intimate contact with their environment.The order of decrease in different tissues when exposed to sub-lethal dose wasobserved to be L>H>G>K>Mwhile exposure to lethal concentration changed the order to K>L>H>G>M. This suggests the fact that the higher levels of the toxicant affect the kidneyswhile lower levels affect the liver.The decrease in the protein content as observed in thepresent study in most of the fish tissues may be due to metabolic utilization of the ketoacidsto gluconeogenesis pathway for the synthesis of glucose, or due to directing the freeaminoacids for the synthesis of proteins, or for the maintenance of osmo and ionic. The lipid levels also decreased in the tissues of the fish exposed to the sub-lethal and lethal concentration of cadmium chloride. Effect of cadmium on the lipid content was reported by earlier investigators .The decrease in the lipid level is as H>M>G>K>L in fish exposed to sub-lethal dose and the order is H>M>L>K>G in fish exposed to lethal dose.