Fish meal, or fishmeal, is a commercial product made from fish and the bones and offal from processed fish. It is a brown powder or cake obtained by drying the fish or fish trimmings, often after cooking, and then grinding it. If it is a fatty fish it is also pressed to extract most of the fish oil.Fishmeal is a nutrient-rich and high protein supplement feed ingredient that stores well, and is used primarily in diets for domestic animals and sometimes as a high-quality organic fertilizer.Fishmeal is made by either cooking, pressing, drying and grinding of fish or fish waste to which no other matter has been added. It is a solid product from which most of the water is removed and some or all of the oil is removed. Four or five tonnes of fish are needed to manufacture one tonne of dry fishmeal.There are several ways of making fishmeal from raw fish; the simplest way is to let the fish dry out in the sun. This method is still used in some parts of the world where processing plants are not available, nevertheless the end product is poor in comparison with ones made by modern methods. Nowadays all industrial fish meal is made by the following processes:[2]Cooking: A commercial cooker is a long steam jacketed cylinder through which the fish are moved by a screw conveyor. This is a critical stage in preparing the fishmeal, as incomplete cooking means that the liquor from the fish cannot be pressed out satisfactorily and overcooking makes the material too soft for pressing. No drying occurs in the cooking stage.Pressing: A perforated tube with increasing pressure is used for this process. This stage involves removing some of the oil and water from the material and the solid is known as press cake. The water content in pressing is reduced from 70% to about 50% and oil is reduced to 4%.