FISH FOODS

The species of fish usually sold as feeder fish are invariably some of the easiest fish for fishkeepers to rear and breed, such as goldfish and guppies. Typically, these species are tolerant of overcrowding and have a high fecundity and rapid growth rate. This makes it easy for fish farmers, retailers, and hobbyists to maintain large populations of these fish that can be sold at a much more affordable price than the more delicate ornamental fish that require better conditions.
In some cases, species of predatory animals, typically large fish such as catfish and cichlids but sometimes also animals such as freshwater turtles, are provided with feeder fish because they accept them more readily than alternatives. Other animal keepers believe that feeder fish are particularly nutritious, being what their pets would eat in the wild. Still others view feeder fish as a stimulating treat that encourages predatory animals to exhibit their natural hunting behaviours. Some animal keepers enjoy watching the hunting and eating techniques involved when one animal eats another.

The mosquitofish, Gambusia affinis, is native to southern and eastern portions of the United States. Originally introduced into California as early as 1922, they have been one of the most effective non-insecticidal and non-chemical methods of controlling mosquitoes for over eighty years. Mosquito fish do not lay eggs, but rather give birth to live young. These fish, therefore, require no special environment, as most other fish do, for depositing and hatching their eggs. They breed throughout the summer and new broods are produced at intervals of about six weeks, with 50 to 100 young in a single brood. The young are approximately 1/4 inch in length when born and grow to a maximum size of about three inches. They are ready to begin the work of destroying mosquito larvae at once. Mosquitofish can eat mosquito larvae as fast as the larvae hatch from eggs, as many as 100 per day. The earliest brood of the season, born in April and May, become sexually mature and produce young when six to eight weeks old. Mosquitofish live 2-3 years and can tolerate a wide range of temperatures.

Aquarium fish feed is plant or animal material intended for consumption by pet fish kept in aquariums or ponds. Fish foods normally contain macro nutrients, trace elements and vitamins necessary to keep captive fish in good health. Approximately 80% of fishkeeping hobbyists feed their fish exclusively prepared foods that most commonly are produced in flake, pellet or tablet form.[1] Pelleted forms, some of which sink rapidly, are often used for larger fish or bottom feeding species such as loaches or catfish.[citation needed] Some fish foods also contain additives such as sex hormones or beta carotene to artificially enhance the color of ornamental fish.

Dry foods
Flake food is a type of proprietary or artificially manufactured fish food consumed by a wide variety of tropical and saltwater fish and invertebrates. It is ideally suited to top dwellers and mid-water fish though numerous bottom dwelling species consume flake food once it has settled on the bottom. Flake food is baked to remove moisture, ensuring a longer shelf life.[citation needed] Generally the more moisture a particular example of fish food contains, the more readily it will deteriorate in quality.[citation needed]
Dry foods is also available as pellets, sticks, tablets, granules, and wafers, manufactured to float or sink, depending on the species they are designed to feed.

Pellet fish food is generally suitable for mid-water feeding fish and bottom dwellers. Mid-water fish usually prefer to swim in the middle area of the tank, though they may occasionally also investigate the bottom of the tank. Most mid-water fish prefer to have their food delivered to them in a highly visible form, such as that of fish pellets. Pellet fish food formulas usually sink quite rapidly, and will be able to be consumed by mid-water fish as they drop. Since pellets often descend to the bottom of the fishtank, they are also suitable to be used as a food source for bottom-dwelling fish. Most bottom-feeding fish prefer to browse the bottom of the tank for their food-based needs.
An advantage of pellet based fish food formula is that it does not tend to deteriorate as rapidly once submerged in the water of the fishtank. Most flake fish food formulas break apart once they reach the bottom of the tank, and may slip underneath sand or gravel. This promotes growth of bacteria, as bottom-feeding fish may not be able to reach the food particles. Pellet fish food formulas are better able to retain their shape, and are more readily consumed by bottom-dwelling fish.

Worms
Black Worms
Blackworms are segmented worms typically raised on fish farms (hence significantly cleaner than Tubifex worms).
Tubifex Worms
Tubifex inhabit muddy, polluted streams and cannot be recommended as fish food because they harbor parasites and toxins, and have a low beneficial nutrient content. Always soak the worms in water for several days before feeding. Feed sparingly as uneaten Tubifex worms will burrow in the gravel and may die. Tubifex worms are only good to feed temporarily, if fish refuse all other foods.
White Worms (Enchytraea)
White worms are found in decomposing materials including compost piles and seaweed piles. White worms are fatty and should only be fed on an occasionally basis. White worms are commonly used to feed older fry. These worms can be cultured at home.