Vitamins

Fish require a certain number of vitamins for good growth and health, the amount varying according to the age (and health) of the fish. They are all present in the dietary raw materials but processing and subsequent storage can result in variable levels being left when the time comes to feed the fish. As a result the raw material is assumed to contain no vitamins and sufficient amounts of synthetic vitamins are added during the manufacturing process.

Vitamins fall into two categories - water-soluble and fat-soluble. The former includes Vitamin C and various B vitamins (B1, B2, B6, B12) and the latter Vitamins A, D, E, and K. All these vitamins and several others are added to feeds in small amounts (e.g. 10-500 ug per kg dry weight of food).

Note: the fat-soluble vitamins can accumulate in fish and cause vitamin poisioning of hypervitaminosis. A lack of vitamins in the diet can lead to growth and health problems.