Approximately more than half of the world’s population does not get enough protein and the entire Asia, Africa and Latin America suffer from malnutrition. In view of the rapid growth of the world’s population, it is advisable to have healthy cultivation of fish which has been an important source of very rich, palatable and easily digested protein. About 50% of fish population is lost due to fungal and bacterial infection of fish at egg, fingerling as well as adult stage. The control measures, in practice, are use of pure and synthetic chemicals which are mostly toxic to the fish or cause residual toxicity to the consumers; and use of natural biochemicals is not cost effective. Use of Trichoderma viride as the “Perpetual Bioremediation System” (PBS) has been found to be 100% effective against fungal and bacterial fish-pathogens and ton-toxic to the fish population as well as safe to the consumers. If the suggested method is implemented to all the fish-culture centres in the country, it may cause negligible mortality and may result in the boost in fish production of the country and will help in national economy.