Toxicology is a field of science that helps us understand the harmful effects that chemicals, substances, or situations, can have on people, animals, and the environment. Toxic chemicals may have a direct effect on the fish immune system by reducing resistance to infectious disease. Toxic chemicals may also have indirect effects on the environment causing stress in fish or affecting the proliferation or survival of pathogens. In all earnestness, this author has tried his level best to make use of the available facilities to give a concise effort to study the problem undertaken. The researcher...