Feeding your Fish

As a beginner you will likely be tempted to buy only packaged dried foods, of which there are types to suit almost every variety of fish. Huge amounts of time and money have been expended in ensuring that they provide all necessary dietary elements, and, of course, are palatable. They are incredibly convenient for the aquarist but … how would you like to live your entire life on convenience foods, or even chocolate bars? You need only feed flake and live foods simultaneously to see how much fishes appreciate the “wriggle factor”. Most fish, are carnivores or at the very least, omnivores, so they prefer live food.

First, of course, you must consider the requirements of individual species. In their natural habitats fishes consume a variety of items other fishes, aquatic and terrestrial invertebrates, vegetation, and so on. Some are opportunistic feeders, eating anything remotely suitable that comes along, and have a generalized digestive system to match.

You must consider whether your sensibilities will allow you to keep species that will eat only live prey, particularly live fishes. Don’t try to convince yourself they will learn otherwise when they get hungry; if thousands of years of evolution have conditioned a fish to react only to live prey, it simply won’t recognize anything else as food. It may perhaps learn eventually that anything you put into the tank is food, but then again it may not. It will certainly need live prey initially. So never buy a fish unless you can reconcile your conscience to feeding it what it needs.

While what to feed is largely a case of homework, how much is another matter, to be learned only by observing your particular mix of fishes. “As much as is eaten in five minutes” is an oft-quoted formula all very well, but how much is that the first time you do it. The trick is to keep giving small amounts until interest wanes; and always siphon off uneaten food after every meal unless you have scavengers who will clear it up, in which case you must use your own judgment as to how much to leave.

How often should you feed?
Well, that depends. If you have a piscivore which in nature eats one fish half its own size every other day, feed it that often. Fishes which feed continuously benefit from several small meals per day. Juveniles grow faster if fed more, and seasonal breeders need more to bring them into spawning condition. On the other hand, coldwater fishes kept in outdoor ponds shouldn’t be fed at all during the colder months when they are inactive. Most aquarists overfeed, if only because feeding evokes a response from their pets. Perpetually bloated bellies, however, (except in gravid females) are as much a sign of ill-treatment as hollow ones.

The following are some of the different types of foods that can be used:

Dried Foods
There is no denying that dried foods such as flakes and pellets can, used sensibly, be a useful basis for the diet of many aquarium fishes, ensuring all the necessary proteins, vitamins, trace elements, and so on. There is an enormous choice available, and initially the best course is to buy the type which your fishes have been fed previously. Be aware of the dangers – apart from boredom – of using dried foods alone: unlike live foods they contain no coarse roughage, and fishes fed only on dried foods (especially by over-generous owners) often suffer digestive troubles and/or constipation, which can easily be fatal. Dried foods swell when thoroughly moistened, with potentially disastrous consequences if, as sometimes happens with greedy individuals, this takes place in the stomach. Avoid this by feeding sparingly when appropriate.

Pond Foods
Most fishes relish anything that can be found swimming or crawling around in a pond (though for reasons of conservation do not feed them frogs, toads, newts, or their tadpoles). The most commonly used pond foods are Daphnia (water fleas) and bloodworm (midge larvae), both available commercially. Others for example Bosmina, Cyclops, mosquito larvae, and, for larger fishes, water boatmen you will normally have to catch for yourself. Some aquarists prefer not to use such foods for fear of introducing diseases and/or parasites, but this is highly unlikely, as ponds containing fishes (the source of diseases and parasites) tend not to have populations of live foods worth collecting! Do beware of predators such as dragonfly larvae and Dytiscus marginalis (the great diving beetle), which will eat small fishes and damage larger ones. Pond foods can be an essential element in conditioning breeding stock, and contain beneficial amounts of roughage. Many are now available frozen or freeze-dried (fishes appear to prefer the former).

Pond foods are much enjoyed by most fishes, and are excellent conditioning foods. Daphnia (water fleas) are common in duck ponds, as are mosquito larvae which can also be found in smaller bodies of water such as cattle troughs.

Other Live Foods
Earthworms, enjoyed by many fishes, can be fed whole or chopped to suit mouth size. Woodlice (collected) and crickets (bought) are suitable for larger mouths.

Whiteworms and grindal worms are small worms cultured in boxes of loamy soil. Starter kits can be obtained from dealers or by mail order. But feed only in small quantities as they can be fattening and constipating.

Tubifex are small red worms which live in mud (often around sewage outfalls) and are available from dealers. Always wash them before use. Although fishes enjoy them, you use them at your own risk, as their habitat makes them likely carriers of disease. Frozen or freeze-dried Tubifex are considered safe.
Before feeding to fishes, earthworms should be rinsed under the tap, or in a bucket of water, to remove any soil particles.

Artemia (brine shrimp) nauplii can be hatched from eggs for feeding fry; adults can be purchased for larger fishes. They should be rinsed in fresh water before use, to remove salt residues.

Live fishes used as foods are usually surplus fry, deformed or damaged (never diseased) specimens, or cheap, readily available aquarium fishes (often livebearers and goldfish). There is always a chance of introducing disease, so this diet should be used only where essential; never use wild native fishes.

Hatching Artemia (brine shrimp)
Brine shrimp are usually hatched in clear, preferably glass, containers (such as large bottles) filled with salt solution, which should be made up according to the instructions accompanying the eggs. (In the absence of any instructions, use 25 g (1 oz) of marine or cooking salt per litre (2 pints) of water.) The containers should be stood in a warm place 18-24 C (65-75 F) and strongly aerated so that the eggs do not settle (if they “clog” on the bottom, the hatch rate will be greatly reduced).

When the eggs hatch, usually after 2-3 days, the nauplii (baby shrimps) can be harvested. Turn the aeration off and stand a light next to the container so that an area halfway up one side is brightly lit. The shrimps will be attracted to the light and can be siphoned off (using airline tube) relatively free of unhatched eggs and empty shells, which tend to sink to the bottom or float on the surface. Strain the shrimps through a fine net (to avoid adding salt to the aquarium).

Always remember to turn the aeration system back on. Cultures will remain active for only a few days, so 3 should be started at 2 day intervals to ensure a succession of shrimps. Each can then be restarted from scratch on its 7th day, for as long as required.

Frozen and Freeze-dried Foods
These are available from most dealers, and represent a safe and convenient way of feeding pond and other natural foods. Frozen foods are, however, expensive and have a high water content, while freeze-dried ones are not always enjoyed, at least not at first.
A selection of human foods suitable for various

Frozen and freeze dried foods are a safe and convenient way of feeding “live” foods. Frozen foods come in bubble-packed blocks or in plastic envelopes; small organisms such as Tubifex and bloodworm are usually freeze-dried in cubes while larger ones, such as river shrimp, are processed singly.

Human Foods
A number of excellent foods can be “borrowed” from the kitchen ox heart, liver, prawns and shrimps, mussels and other shellfish, cooked chicken, raw and cooked fish, and cod roe for carnivores; cucumber, courgette, peas, lettuce, and spinach for herbivores. Beware of feeding too much mammalian protein, which can cause digestive upsets and fatty degeneration of the tissues. fishes. As long as additives are avoided, the only real limitation is your imagination.
Last, but not least, always regard feeding time as an opportunity to observe your fishes: to make sure they are all present and healthy, and that they are all getting their share.