Dried foods include the familiar flake food, pellets, tablets, and powder fry food.
Nutritionally these foods are complete, in that (assuming they are in date and stored correctly) will contain all the vitamins and nutrition a fish needs. Obviously there are certain exceptions (some fish need extra vitamin supplements, such as halfbeaks, and others will not eat anything that is not alive, and moving!)
Of course fish like variety in their meals, and while they can be given prepared foods as a staple, most will relish a treat of livefoods, frozen foods or simply different prepared foods.
One major disadvantage of prepared foods is their propensity to foul water when uneaten, and the ease at which one can overfeed. If you have an explosion of snails, it is most likely the result of continual overfeeding with dry foods.
Flake Food Flake is designed to float, and sink very slowly, providing a food source for fish that inhabit all stratas of the aquarium. Different flake foods are available for tropical freshwater, marine, and coldwater fish - plus special recipes: spirulina for vegetarian fish and earthworm flake.
Pellets and Wafers Pellets are designed to sink more quickly than flake. Micro-pellets are tiny, but the majority of pellet foods are for larger fish, specifically cichlids and catfish. Algae wafers are perfect for largely vegetarian species.