The type of food given to tropical fish depends largely on their natural dietary requirements. The categories of fish that suit a particular diet can be split into six primary groups; Carnivore, Omnivore, Herbivore, Limnivore, Piscivore and Parasite. These classifications are used Fish Information Index (FINDEX) to identify the fishes primary diet and are explained below.

Note: whilst a fish may be classed a Herbivore, this indicates the fishes primary diet consists mainly of vegetable matter however, it may also accept meat as part of its food intake. Just as humans are Carnivorous, we do not exclusively feed on meat.

Carnivore

Meat-eater. The majority of these fish are predators but this classification also includes any fish which consumes a primarily animal based diet. This may include eating mosquito larvae, worms or flies. For most fish, the food need not be live as they often readily accept frozen or freeze dried foods.

Within these fish the intestinal tract is short and the stomach large thus they tend to eat a large amount in infrequent sittings. Large predators often consume one large meal and spend from several hours to several days digesting it.

Omnivore

General diet. Omnivores are the easiest fish to feed as they readily accept dried foods although a mix of foods is more desirable.

Herbivore

Vegetable diet. In their native habitat, these fish feed on plants, algae fruit and seeds. It is rare that a fish will exist exclusively on a vegetable diet and thus alternative foods such as meat or flake should be offered as a supplement.

Herbivores usually do not possess a stomach as such, but instead have an expanded intestine. These fish feed little but often, preferring to snack several times throughout the day.

Limnivore

Mud-eater. Perhaps an easily misinterpreted term, limnivores feed on algae and the micro-organisms that live within the substrate. These fish will also feed on small worms and shell fish such as snails.

Thees fish have a small stomach and a long intestine and will feed almost continuously throughout the day. Tablet foods are often the best method to feeding these specialised fish.

Piscivore

Fish eater. Primarily predatory fish that live solely on a "cannibalistic" diet. These fish must be fed live foods.

Parasite

These live off other fish opposed to feeding on other fish like Piscivores.

There are two types of parasite; Facultative Parasites, fish that are parasites in nature but will accept normal diets in the aquarium and Obligatory Parasites, such as eye-biters and blood suckers which continue their natural life-style even when offered alternative foods.