Proteins: Proteins are the ones which build the muscles of the fish and also provide them with sufficient energy. Deficiency of Proteins will result in the slow growth of the fish.Excessive feed of protein is also not good in terms of health for the fish and it also increases the cost of feed.


 
Fat: Fat provides energy to the fish. If a proper and correct amount of fat is included in the feed, then it increases the taste of the feed, whereas if the fat content is given in a high quantity to the fish, then it leads to harmful health hazards to the fish.
 
Carbohydrates: Carbohydrates are also considered to be the source of energy to fish.But the disadvantage with these carbohydrates is that most of these will not get digested easily by ordinary carnivorous manne species.
 
Vitamins: Vitamins are organic compounds which are very much important for the fish for its health and growth.The fish cannot synthesize them always. Hence, the vitamins have to be supplied to the fish through its diet.
 
The fat-soluble vitamins are vitamin A, retinol, which is responsible for clear vision, Vitamin D, cholecalciferol, which is responsible for maintaining the integrity of bones; E vitamins, the tocopherols which act as antioxidants; and K vitamins, menadione which help the blood without clotting and also maintains the integrity of the skin. Of all these vitamins, vitamin E isthe most important one as it acts as an antioxidant.
 
Minerals: Minerals are the inorganic elements which are very much required for the fish to carry outtheir normal functions of the body. Minerals can be divided into two types depending on thequantity required in the fish's diet and the amount which is already present in fish.
 
Micro-minerals: Micro-minerals (trace minerals) are just needed by fish in little amounts as components in enzyme and hormone systems. The most common trace minerals are copper, chromium, iodine, zinc and selenium. Fish can absorb most of the minerals from the water directly though their gills and skin. This helps them to compensate deficiencies in minerals to some extent in their diet.
 
And if you have a fish farm and want to know some about feeding fish ,maybe you can come to see the fish feed extruder machine in Lima.