Fish is good food to man. The flesh of flesh is rich in proteins and fat. Dry fish also contains A and D vitamins. It contains minerals. Much of the flesh can be digested by man. Food fishes are both marine and fresh water.
Ex: Labeo, Catla, Trygon, etc
2. FISH BY-PRODUCT
Fish Oil: From the liver of the many fishes oil is extracted.
A. Cod liver oil: It is extracted from the cod fishes.
B. Shark liver oil: It is extracted from the liver of the shark. These oils contain A and D vitamins.
C. Bombay duck oil: The Extracted oil from Bombay duck is used in Paints.
Fish meal: Many fishes are dressed and cooked. Then they are dried. Fishes are made into fine powder. This is called fish meal. It is used by weak and convalsent people.
Isinglass: It is a pure gelatin substance. it is obtained from air bladder of the fishes. it is used to clarify wines.
Fertilizers: The ‘fish waste’ materials have more calcium, protein, phosphorous and other substances. These materials are grined into powder. It is used as fertilizer to Grape gardens, Coffee and Tea plants.
3. CONTROLLING DISEASES
Some of the fishes like Gambusia barbus will eat the larval forms of mosquitoes. Thus they prevent the spread of malaria disease.