In this group, you will for instance find flake food, pellets and wafers. Flake food is the most commonly used food by beginner fish keepers, but even advanced aquarists frequently use high quality flake food as the base food of choice for their fishes. Pellets are a good choice for larger fish, since a big fish can find tiny flakes unsatisfying. Algae wafers are popular among Plecos and other algae eating bottom feeders.
If you keep herbivore species, you should seek out prepared foods high in vegetable and/or algae matter, such as green flakes and algae wafers, while carnivore and omnivore species should be given manufactured foods rich in protein. If you give herbivore species food high in protein and low in fiber, they can develop health problems. Foods made from Spirulina are a notable exception, since they can be high in (vegetable) protein without being dangerous for herbivore fish in any way. Fatty manufactured foods should always be avoided since fish hardly ever eat fatty foods in the wild.
The quality of manufactured foods varies dramatically and it is therefore important to choose the right producer. Avoid foods that are chiefly made up by wheat flour filler. Foods that contain potentially harmful additives must naturally also be refrained from. Do not hesitate to ask more experienced aquarists for advice regarding which brands they have had success with in the past.
The way manufactured foods are stored will also have a dramatic effect on their nutritional value. If you for instance place them on top of hot aquarium lights, they will rapidly loose a lot of their nutrients. Store prepared foods according to the recommendations from the manufacturer (normally in a dry, somewhat cool place) and only purchase food from pet shops that store their products properly. Check the manufacturing date and the best-before date and do not purchase or use old products.
Freeze-dried foods will normally have one single ingredient, such as mosquito larvae, blood worms or similar. Sometimes you will be able to distinguish the individual organisms, in other cases they will be sold as form pressed sheets or chunks. Since they contain a single organism they do not aspire to be a complete diet – they are instead used to supplement other types of food and make the diet of your fish more varied. Ideally use several different types of freeze-dried foods since this will give your fish even more variation. Freeze dried food is popular among aquarists who do not wish to store food in their freezer and go through the process of thawing it before each feeding. Just as with manufactured foods, it is very important to store freeze-dried products under optimal conditions and refrain from using old products.
You can purchase commercial frozen food or cultivate a large batch of live food at home and freeze it into suitable serving pieces. Homemade food preparations can naturally also be frozen to preserve their nutritional value over time. If you visit your local fish store, they will probably have a freezer filled with various frozen fish foods, such as crustaceans, mollusks, insects and fish. Keep in mind that frozen foods need to be thawed before you serve them to your fish. You can keep a suitable amount defrosted in your fridge.
Making your own fish food mixture can prove financially sound in the long run, especially if you want to give your fish something else than a diet consisting of cheap flakes only. The cost of the food will naturally depend on which type of ingredients you use and how low a price you manage to obtain them for. One of the main reasons why aquarists start to make their own fish food is however not money; it is the appeal of gaining full control over what you give your fish. In some cases, aquarists have even managed to invent special blends that will coax reluctant fish species into spawning in captivity.
If you want to make your own fish food, there is an abundance of recipes to be found online. Ideally try to find a recipe that is recommended for your particular species or group of species. A mixer or food processor will make it much easier for you to make your own fish food, since it will help you to chop the ingredients and turn them into a fine paste. In most recipes, unflavored gelatin is used to bind the ingredients together and make the food less messy.
Varying the diet of your herbivore species is actually very easy, because most herbivore fish species love vegetables. Fish species that feed on plant matter in the wild need large amounts of fibers in their diet, otherwise the can easily develop constipation and other health problems. Feeding your fish vegetables is a great solution to this problem, since vegetables are packed with fibers. You can for instance slice up zucchini and eggplant and quickly boil the slices before giving them to your fish. Holding spinach leaves and lettuce under the hot water faucet for ½ minute will also create a nice meal. If you want to avoid fouling the water, you can use a “feeding-clip” to attach the vegetables and remove any uneaten food each day. Soon your fish will learn where to look for tasty greens.
Many aquarists work really hard to keep their aquariums as free or algae as possible. The truth is however that if you can stand the sight of some algae in your aquarium, you will provide your fish with a natural source of food. Even strictly carnivore fish species will always ingest small amounts of algae in the wild, thereby getting a steady supply of certain nutrients that cannot be found in meaty foods. For herbivore species fond of algae, the act of grazing algae will not only provide them with nutrients, it will also allow them to carry out their natural feeding behaviors in the aquarium.
Plecos and similar species eat small amounts of wood in the wild and will therefore highly appreciate a piece of driftwood in the aquarium. You may not even notice it, but they will slowly rasp away tiny pieces of wood with their specially adapted mouth.
Most aquarium shops culture live foods and offer it for sale, from big goldfish down to tiny brine shrimp. Purchasing live food is a practical solution if you can afford it, but it can introduce disease to your aquarium. The risk is especially high with feeder fish, since any malicious microorganism that have infested the feeder fish will love to infest your fish as well. There are even dishonest pet shops that sell unhealthy fish as feeder fish instead of euthanizing it or putting it in a quarantine aquarium, but there are also many pet shops that do everything in their power to ensure that their live food is free of disease. Examples of commonly sold live foods are feeder guppies, adult brine shrimp, black worms and white worms.
A lot of different live foods can be cultured at home. Some are really easy to cultivate and handle while others are quite messy and arduous to raise. You can find several guides here at AC Tropical Fish, and an online search will provide you with even more information. If you want to raise feeder fish, e.g. Danios, look in the fish breeding section. Examples of commonly raised live food are brine shrimp, white worms, compost worms, and wingless fruit flies. Fish fry will appreciate tiny live food, e.g. infusoria, microworms and newly hatched brine shrimp.
Ideally feed your live food right before you serve them to your fish. This way they will be extra nutritious when your fish devours them. Many predatory fish species will for instance derive a lot of important vitamins from the stomach content of herbivore animals and can suffer from nutritional deficiencies if only given “empty” animals. This is naturally true for live food that you purchase from the pet shop as well. A newly hatched brine shrimp will for instance loose the bulk of its nutritional value within a few hours if not given more food once its yolk sac has been consumed.
If you do not like the idea of raising fruit flies, worms and their kind inside your home, you can always go for a walk and collect wild live food. Choose your hunting grounds with care, because some spots are less suitable than others. Areas sprayed with insecticides or exposed to farm chemicals should be avoided and you might also wish to stay away from polluted roadsides to be on the safe side. Always stay away from bodies of water that looks suspiciously “clean”, e.g. completely free of algae or inhabited by only a low amount of mosquito larvae when the rest of the area is teaming with mosquitoes and their offspring.
Collecting tiny live food is generally considered safe, but it is best to stay away from waters inhabited by fish since it can introduce fish-dwelling parasites to your aquarium. A short-lived puddle that forms after a rainstorm is much safer than a fish filled lake. (It should however be noted that healthy and well fed adult fish kept in a suitable environment tend to be able to combat small parasite attacks and similar without much ado.) One unwanted stove away that you can get even from puddles is Hydra, but this animal is normally only a problem if you have tiny fish fry. If the Hydras get out of control, you can use a double dose of Aquari-sol or similar product to kill them. Bigger water bugs can also try to eat fry, but they will normally be devoured by adult fish before they get a chance to start reproducing in your aquarium. To be extra safe you can avoid using collected live food in your fry raising aquariums and reserve them for big-fish tanks only.
A fine-mesh fish net is ideal for live food hunting, ideally one with a long handle since this will be more comfortable for you. If you go to really transient puddles, you will most likely find mosquito larvae and fairy shrimp. More long-lived ponds can for instance be home to ample amounts of Daphnia. The exact species will naturally vary depending on where you live and during which season your go hunting.
When you have caught an ample amount of bugs for your aquariums, check the sides of your bucket for leaches and pond snails unless you want to add them to your aquarium. If you plan on using the food in aquariums with small fishes, pass your catch through a wide-mesh net to remove the biggest bugs.
If you get a large catch of bugs, you can freeze them to preserve their freshness. Freezing them will also kill off certain types of parasites, but it will of course also take the “live” out of the “live food”.