By Donna M. Recktenwalt
As aquarists, we know that feeding our fish a variety of quality foods is important, and we have developed a good feel for how much to feed at any given time.
To be healthy, fish require appropriate conditions (water, temperature, appropriate tank size, compatible companions), light, and food. Since an aquarium is an unnatural situation, the aquarist must also be observant, to see that all the fish are eating, not just the bolder individuals. If fish receive too little food or food inadequate to their nutritional needs, they will merely survive at the expense of good color, vitality, and reproduction.
Feeding fish is more than just dropping a pinch of dry food into the tank once or twice a day. For fish to be healthy and show their best colors, they require a diet that fulfills all their basic nutritional needs. If we want the fish to be well nourished, we need to understand their needs and requirements and feed them good food.
Like humans, fish require a diet containing a balanced mix of fats, carbohydrates, protein, vitamins, and minerals. If so inclined, the aquarist can make quality fish foods at home, using fresh or frozen ingredients and already proven formulae. However, most commercially available dry and flake foods meet basic piscine requirements and form a good basis for their diet. Lee Harper has used ground Purina Trout Chow as the basis for his fish feeding regimen for years. However, even for fish that are not being stressed by breeding, it’s a good idea to use a variety of formulations in addition to the occasional live foods, to provide variety.
How Much and How Often to Feed?
In nature, fish feed continually. In the aquarium, the aquarist controls the feeding cycle not only by the selection of foods, but by the choice of feeding times.
Most aquarists recommend feeding at least twice a day, with more frequent feedings for fry. With dry foods, feed as much as the fish will clean up in about five minutes; after that, most foods will begin to pollute the water. Some live foods, such as daphnia, glassworms, mosquito larvae, and bloodworms, may be left in the tank with the fish for “snacking” later. Tubifex worms may burrow into the substrate, out of reach of the fish. If not eaten in a day or two, mosquito larvae may reach their adult form; be forewarned that for them, the aquarist may make a good meal!
If you choose to feed only once a day, morning is preferable. In well planted aquaria or those with green water, chlorophyll in the plants generates oxygen (O2) in the presence of light and releases carbon dioxide (CO2) when dark. Fish require extra oxygen in order to aid digestion. Feeding early in the day assures that plenty of oxygen is available, particularly in aquaria with heavy fish loads. In aquaria with less fish, the actual feeding times are less critical.
Feeding Breeding Fish
Breeding fish are under greater nutritional stress than are fish merely maintained in an aquarium. In addition to meeting their own basic nutritional needs, they must also develop strong eggs and sperm, and have sufficient energy for courting and spawning. For breeding fish, the addition of live foods is highly recommended. However, observation by aquarists have shown that some live foods are more beneficial than others.
Brine Shrimp:Newly hatched brine shrimp nauplii are an excellent food for any killifish, from those newly hatched fry large enough to take them, up to breeding adults. However, egg production by adults fed solely on brine shrimp nauplii has often been minimal. Adult live or frozen brine shrimp are also good, although some loss of nutrition occurs during the thawing process..
Worms (earthworms, bloodworms, tubifex worms, whiteworms, etc.): Feeding worms has long been known to increase egg production in breeding fish. Earthworms, tubifex worms, glassworms, and whiteworms are particularly good, as are fresh or frozen bloodworms. Black- and tubifex worms have a dubious reputation, and should be used with care.
Mosquito Larvae: When available, this is probably one of the best possible live foods for any killifish.
Daphnia: When used with brine shrimp, daphnia can increase egg production, but not to the extent that tubifex will.
References:
Speice, Paul. “Guppies to Groupers,” Freshwater and Marine Aquarium, January 1986.