What else do fish farmers do to maintain healthy fish?
Two things are especially important. First, feeds must be correctly formulated for the species that is being farmed and for the life stage that is being fed. There have been major advances in fish nutrition in recent years and it would now be extremely rare for any sort of nutritional deficiency to compromise the health of fish in farms. Second, stocking densities must be maintained at levels so that the fish are at ease. Appropriate density levels vary for different species, different life stages and it depend on factors such as water temperature. A typical maximum density for larger fish in typical conditions in cages, such as salmon, would be 20kg per cubic meter (1000 liters of water), or, expressed another way, the fish would occupy 2% of the total rearing volume.
