Types of fish food

Fish foods come in a variety of forms: dry formulations, livefoods, freeze-dried and deep-frozen preparations are the main types. Some are intended for general use, other for specific purposes.

Dry Formulations

They are available as flakes, pellets/granules and sticks. All come in a variety of sizes, from fine, almost-powdery foods designed for very young fish, to large grains or sticks for large adults such as Koi. There are "staple" recipes for everyday use;
high protein diets for growing fish and general feeding during late spring and summer;
Carbohydrate-rich (easily digestable), slow sinking formulae for colder weather use;
Spirulina-enriched foods for enhanced colorations;

Livefoods

They are commonly used as a natural dietary supplement. Despite the versitility and good value of the best dry formulations, most pond keepers like to vary the diet for their fish by providing livefoods, at least occasionally. While it is debatable whether this has any measurable effect on nutrition, fish appear to relish livefoods.

The most widely available types of livefood include:
Daphnia (waterfleas),
Adult Artemia (brine shrimp),
Tubifex (tubificid worms)
Chironomus  (bloodworms)
If these come from cultured stocks, they are likely (with the possible exception of Tubifex) to be pathogen-, parasite-, and predator-free.

Freeze-dried Foods

Consist of livefoods whose moisture content has been virtually eliminated. The processing of these foods also results in the destruction of most pathogenic agents, thus making them very safe, while retaining their nutritional value. Freeze-dried foods come either loose or as small compressed blocks. Loose, small organisms, such as Daphnia, Chironomus and Tubifex, are particularly suitable for small fish. Larger items, such as shrimps of various types, can be fed to larger fish, which also like cubed preparations.

Deep-frozen Foods

Originally consisted of single (i.e unmixed) items such as bloodworm, Mysis shrimps and the like. In more recent years, mixed diets have been introduced, partly as a result of research carried out on formulations for marine fish. Most deep-frozen foods are gamma-irradiated, which destroys pathogenic organisms and makes the food very safe to use.

Other Foods

Includes fresh vegetables, such as garden peas and bruised lettuce, along with crumbled biscuits, brown bread, and other unprocessed items. Modern innovations include high-nutrition foods containing immuno-stimulants to increase resistance to infections.