Heavy metal contamination has posed a great threat to aquatic systems all over the world. Fishes are commonly selected to test aquatic pollution because they are most susceptible organisms in the aquatic ecosystem. Nickel is an important heavy metal but it causes Liver damage on accumulation. Nickel is discharged into freshwater habitats through atmospheric deposition by nickel mining, smelting, industries, oil and coal burning power plants and trash incinerators. Liver is the chief organ that contains large amount of enzymes and plays an important role in metabolism, excretion, secretion, detoxification and storage. Alteration in liver enzymes concentration helps in diagnosis of disorders in certain tissues by toxins. This Book describes how the high nickel metal concentration damages the liver of fish Labeo rohita which is used as major sea food throughout the world, metal toxicity can be ultimately transferred to human beings, Thus this research also evaluates nutritional value of the fish.