Foods and Feeding: Freshwater

From Microcosm Aquarium Explorer

Chromobotia macracanthus feeding.jpg

Bottom feeders need special attention in a community tank. (Chromobotia macracanthus).


Creating the right menu for healthy, colorful fishes

In the not-so-distant past, aquarium fish were fed things such as ground puppy biscuits and inferior flake foods composed of the same ingredients, including wheat flour and salt, used in making breakfast cereals and crackers for human consumption.

Today, we know that good nutrition is one of the keys to maintaining a healthy and prosperous aquarium, and providing our charges appropriate foods certainly ranks high on the list of things we need to get right. Fortunately, the foods available to aquarium keepers have improved dramatically in recent years and it is not hard to keep our fishes well-fed and thriving.

To the uninitiated, the idea of feeding aquarium fish can seem pretty simple: once a day, you open a container of fish food, sprinkle a pinch or two on top of the water and watch the fish swim up to eat. Job finished...right?

To do things right and to see your aquarium fishes at their best and most colorful, perhaps even witness spawning behaviors, there is a bit more involved. Like most forms of life (humans included), fishes need a varied and balanced diet that provides for all their nutritional needs. Protein, carbohydrates, lipids (fats), vitamins and minerals are just some of the components that make up a good diet.

Flake Foods & Flaky Foods

Some credit a young German scientist, Dr. Ulrich Baensch, with revolutionizing the aquarium hobby in the 1950s when he developed flake foods formulated to meet the needs of captive fishes. Prior to this, aquarists relied on hard-to-supply live foods caught in local streams and ponds or on pulverized cereal products and foods for other animals. Flake foods helped bring aquarium keeping within the reach of millions more people, but for decades the quality of such rations varied wildly, with many more appropriate for a pet chicken than animals of aquatic origin.

Luckily for aquarists, today there are so many generally excellent prepared foods to choose from that we can easily match the foods to the types of fishes we keep. In place of the heavy doses of wheat flour, the better new foods are rich in fish meal, shrimp meal, krill, fish roe, vitamins, minerals and color-enhancing pigments. Cheap fillers from the bakery industry have moved down the ingredient list in all of the best fish foods.

In addition to well-balanced community-type tropical foods, there is also an increasing variety of specialty, or species-specific, foods such as “herbivore” and “carnivore” diets. There are even foods aimed at a particular fish or group of fishes—betta, cichlid or catfish diets. Then there are the different styles of food to choose from—flakes, discs, pellets, granules of all sizes, sticks, sinking wafers and so on, as well as freeze-dried, frozen and, yes, live.

In fact, if you are new to feeding fishes and try to browse the shelves of a well-stocked aquarium store, you may be overwhelmed by the sheer number and variety on display. There is no need to let all this go to your head. Feeding most of the species in this book is not difficult. The bottom line here, and an open secret, is that most of the foods you see in good aquarium stores will work reasonably well for most commonly kept aquarium fish. The important thing is to provide a variety of different foods. It is possible to feed a community tank with one well-balanced ration, but your fishes will do better if you vary their diets. (Your role as a fishkeeper will also be more interesting and rewarding.)

Setting up Your Fish Food Pantry

So, where to start? While some fish do have special dietary needs that must be taken into account, the nutritional requirements of the great majority of tropical fishes are easily met by providing a varied diet of standard prepared aquarium rations, regularly supplemented with specialty items, such as “meaty” foods or those that are vegetable-based.

A well-stocked fish food pantry will include at least a couple of types of flake foods. There are, of course, the basic rations, typically sold as “tropical flakes,” which are good for most tropical aquarium fishes. Then there are the vegetable-based flakes, which are richer in vegetable matter and usually contain Spirulina algae. Both of these varieties should be included in your pantry.

The idea of providing an assortment of foods is based on the fact that, no matter how good a particular food is, there is always the possibility that it may be lacking in some of the nutrients essential to the well-being of the fish you are keeping. Also, “variety is the spice of life,” even where your fish are concerned. Will they be able to live and even thrive on a diet consisting of just one type of food? Probably...but would they be a bit happier with a variety of foods in their lives? I think so.

Depending on the type of fish you are keeping, you may also want to include one of the “sinking” varieties. In a tank with mostly surface or mid-water swimming (and eating) fishes, it may be difficult for sufficient amounts of food to reach the lower levels of the aquarium, where a number of species, such as the catfishes, spend most of their lives. While some bottom dwellers may quickly learn to come up to the surface for food, others may not be quick learners or have the ability to do so. The styles of foods you choose should take into account the types of fishes you keep.

When it comes to prepared foods, it is best not to purchase too large a quantity at one time. Once opened (and, in some cases, even before), fish foods are subject to nutritional breakdown. Think of a box of breakfast cereal. Within a few weeks, if not eaten, it loses its crunch, takes on a rancid taste and loses its palatability. The vitamin content also suffers. Purchasing smaller containers will allow you to restock your pantry on a regular basis, thereby helping to guarantee good nutritional content of what you are offering. (Bulk fish foods, exposed to the open air, are shunned by most advanced hobbyists.)

Typical “Meaty” Foods

The regular feeding of some types of meaty items should be considered essential unless you are keeping a strictly herbivorous community or species. Offering these foods at least five to seven times a week will go a long way toward promoting fish vitality and health. Many of the commonly available meaty foods come in a number of forms: frozen, freeze-dried and live.

Brine Shrimp (Artemia salina) is a standard food in the aquarium hobby and it comes in a variety of forms, including frozen, freeze-dried and live. Brine shrimp are aquatic crustaceans famously harvested in San Francisco Bay and the Great Salt Lake, but also in other bays and estuaries worldwide. This prolific little animal has the ability to produce egglike cysts that can survive for years in a dry state before hatching within hours after being returned to saltwater. (These are the sea monkeys you might have bought as a youngster.)

While brine shrimp are by no means the most nutritionally complete food, they are still a good addition to an overall dietary profile for many fish. Depending on the need, they may be enriched before feeding with one of the many vitamin supplements, such as Selco™ . (Or, in the case of commercial brands, before freezing.) When feeding the frozen variety, it is best to take the desired amount and let it melt in a container of tap water. (This would be your fish-only feeding container.) The shrimp can then be poured into a fine mesh net and rinsed well under running tap water of approximate aquarium water temperature to avoid adding unneeded pollutants to the tank.

These can then be fed to your fish in small amounts to make sure everything is eaten. You could also add the shrimp in with some flake food. The important thing to remember is not to add the frozen shrimp without first thawing and rinsing. Once you’ve seen the murky fluid and sediments that escape when you add a frozen piece directly into the aquarium, you’ll think twice before doing so again.

Freeze-dried brine shrimp is also available and should be treated the same as the frozen variety. The cubes, or chunks, can be broken up and put into a container of water. You can gently press them with your fingers to help them absorb water (re-hydrate). Then rinse and feed to the fish.

Many stores may also carry live brine shrimp, typically available in set portions. Feeding these can add another level of feeding enjoyment to your fishes by stimulating their prey capture response—they get to hunt the shrimp just as they would pursue live items in the wild. Do not add the water brine shrimp come in to your tank, as it has a high salt content. Treat as with the frozen and freeze-dried varieties.

Bloodworms are the larvae of midge-type flying insects and are relished by practically all tropical fish. Both frozen and freeze-dried varieties are available, and should be served using the same procedure described for brine shrimp. Bloodworms are an excellent food source and should be considered a necessary part of any good tropical fish diet. A word of caution here—some hobbyists are allergic to bloodworms and may develop a rash after coming in contact with them. The frozen chunks can be broken off in the package and added to the thawing container without having to touch them.

Krill or euphausids are shrimp-like marine crustaceans that make an excellent food for tropical fish. Krill are typically available in at least three different sizes, the smallest of which is usually sold as “plankton” and seems to be the size of choice for most fishes. Larger krill can be used in feeding big carnivorous fishes. Again, the frozen and freeze-dried varieties are the most commonly available. Of course, brine shrimp, bloodworms and krill are not the only live foods available. There are also white worms, black worms, Daphnia, glass worms (an insect larvae) and Cyclops, among others. Your local store can help you in deciding which ones to choose.

There are also an increasing number of frozen food mixtures available. These incorporate a variety of foods into an-easy-to-feed mixture, and are usually supplemented with vitamins and minerals. These foods are often targeted for specific groups of fishes (e.g. “cichlid formula”), but are generally a good additional food source for most fishes. Again, the “thawing and rinsing principle” applies here.

Feeding the “Vegetarian” Fishes

In these enlightened times, we must not forget the veggie lovers. While most tropical fish will benefit from having some vegetable material in their diets, there are those, such as the pleco-type catfishes (i.e., Otocinclus spp., Ancistrus spp.), that feed primarily on green matter in nature, and for whom vegetable-based foods are essential.

Flake foods that are high in vegetable material are very good for them, but may often be eaten by faster, surface and mid-water fishes before reaching the fish that truly need them. There are some commonly available vegetable-based foods designed specifically for the groups of fishes that are more compact, and heavier, including discs and wafers, that sink quickly to the bottom. Most of these fishes have rasping-type teeth that will make quick work of these foods . There are also algae-based frozen foods, marketed mainly for marine fishes, that make ideal plant-based meals for these freshwater fishes. (As always with frozen fish foods, don’t forget to “thaw and rinse” to avoid polluting your tank.)

Finally, the use of fresh, or even some canned, vegetables as a supplemental food source should not be overlooked and will be appreciated by many fishes…even some that might surprise you. Darker leafy vegetables, such as Romaine lettuce, leaf-type lettuce, and spinach, are eagerly eaten by many fishes (avoid lighter colored lettuce like heads of iceberg, which is mostly water and cellulose).

Leafy greens are a good choice not only for pleco and other catfishes, but cichlids and a variety of other fishes may also eagerly consume these foods. Be sure to rinse the lettuce or spinach leaves thoroughly under running tap water and then add them to the tank (one leaf at a time is ideal). Because lettuce leaves float, they will need to be secured so that bottom feeders have access to them. There are special clips sold in aquarium stores just for this purpose. You can also use clean, washed rubber bands to attach the leaves to tank decor (rocks, driftwood, etc.) or pieces of stone. Many frozen, or canned, vegetables, packed in water, can also be used and are relished by plecos, as well as other fishes. Green beans (regular or French-cut) are especially appreciated. Again, rinse well and then add them to the tank in small amounts to make sure all is eaten. This is an area where you can experiment, always remembering to use small quantities in case your fish might not like a particular item. As with other foods, after a short period of time uneaten amounts should be removed from the aquarium.

Color-Enhancing Foods

A growing trend in formulating better tropical fish foods is the inclusion of color-enhancing supplements. Of particular interest are the carotenoid pigments (including carotenes and xanthophylls), which can strengthen and enhance the natural colors of the fishes eating them. The colors most commonly affected by these substances are the reds and yellows, but blues, greens and other colors will also show improvement.

It is a good idea to add at least one such food to your basic fish food pantry. You can choose the style of food depending on the fishes you are maintaining. For example, if you are keeping primarily smaller fishes, a flake formula will generally suffice. But, if you havelarger fishes, you might want to consider an appropriate pellet or stick-style food. Just be sure to remember that all fishes can eat smaller foods, while only larger fishes will be able to easily take the larger varieties. Again, when feeding these color-enhancing foods, you want to make sure that all the fishes in your tank are getting their fair share.

How and When to Feed

In the wild, most fish feed naturally throughout the day—or during dark hours if they are nocturnal. In the aquarium, as food is offered, they will eat their fill. For the most part, it is not common for most fish in the wild to consume only one large meal a day. It is actually quite difficult to overfeed most fish, as they tend to stop eating or at least slow down once they are full. Overwhelming the tank’s waste-handling capacities with uneaten food is an easy matter.

A good rule of thumb is to feed your fishes three to four smaller meals a day. No uneaten food should remain after five minutes or so. The spacing of these meals may depend on the fishes being kept and the schedule of the keeper. It doesn’t take long to feed the tank, and it is a perfect time to be able to take a look and make sure that all the fishes are doing and eating well. Again, you can mix and match foods, feeding some flakes and bloodworms one time, and brine shrimp and lettuce the next. In fact, this undoubtedly mimics a more natural feeding process.

If you are keeping nocturnal or timid fishes, be sure to offer them food about a half hour or so after the lights are turned off at night, when the feeding response of the other fishes is reduced. Use some of the sinking varieties or even fresh or canned vegetables. This will help guarantee them their fair share of food. It’s also a good idea to offer food the first thing in the morning when the lights are turned on.

Predatory species may be able to survive on one large meal, but in the typical community setting, they will simply consume the regular succession of smaller portions offered. Even if you have a large pet fish, such as an Oscar, it is probably not a good idea to offer its entire daily ration at one fell swoop. Feeding aquarium fishes is actually quite simple. With a little thought and planning, everything else will fall into place and your fish will be happy and healthy.

Excerpt from: 101 Best Tropical Fishes