There are thought to be over 25,000 different species of fish in the world and the vast majority have their own specific nutritional needs. Whilst this may sound daunting, it is easy to provide good nutrition by following somebasic principles.
As mentioned in the Fish Food section, some fish only eat plants and others only eat animals. However, the majority of aquarium fish are omnivores and eat both plants and animals. It’s important to match the type of food to the type of fish.
The diet offered needs to be appropriate to meet these different needs. In other words, it should deliver an appropriate amount of different nutrients, and be in a format that the fish can easily eat. A good quality prepared food will provide fish with a balanced diet. This will include nutrients such as protein (which supplies the 10 essential amino acids that most fish require), fats (for energy and as a source of essential unsaturated fatty acids), vitamins and minerals. Some fish foods contain pigment enhancers, to bring out the natural colours of the fish (e.g. in the form of ingredients such as shrimp meal, Spirulina algae, and lutein).
Some species of fish are unable to make their own Vitamin C and so must be provided with this nutrient in the diet. Essential Vitamins including A, C, D, E and K are supplied in most complete fish foods.