Feeding your fishes and other aquarium residents is an important part of keeping them alive. Merely buying some flakes at the supermarket and dumping them in once a day may be adequate for goldfish, but most types require a little more thought and effort.
Obviously, small mouths require small foods, and large mouths require large foods. Try to feed small portions several times a day, at least morning and night. Don't just dump it in and walk away - watch as they eat. Give them more if they finish everything and still seem hungry, but do not overfeed. Fish have preferences just like we do, and you may find that they refuse certain types of food outright. Make sure all the residents of the tank get something, and make a note of who eats what and how much.
Store-bought tropical aquarium fishes are probably already used to a diet of prepared dry fish foods, and are easily fed. There is a wide variety of such foods available. Get several kinds, and alternate. This assures that the fish get balanced nutrition, and also breaks up the monotony for them. Types of fish food you might consider stocking are: thin flakes, thick flakes, floating pellets, sinking pellets, freeze-dried bloodworms, and freeze-dried krill. Color can make a difference - for example red foods are accepted more readily than green foods. I buy several types of dry fish food in bulk about once a year.
Although your fish may be happy and healthy on a varied diet of dry foods, if you want to see them eat with gusto, periodically give them some meaty frozen food. The commonest of these are beef heart, worms, and shrimp & fish meal, usually sold in pet stores in frozen slabs or cubes. Use a cleaver to cut the
frozen slab into suitably sized pieces, and store them in an old margarine pot in your freezer. This way you can easily pick out a piece and feed it to your fishes whenever you like. Throw it right in frozen and let then gnaw on it, or thaw it out if you like.
Fish may also be fed raw kitchen scraps. Avoid foods that are salty, spicy, or greasy. Hamburger is far too fatty for fish to properly digest, and also leaves a slick in the water. Slivers of fresh fish, chicken, and lean beef will be relished. Many fishes will include vegetable matter in their diets. Spinach, lettuce, and even bits of fruit may be eaten. Next time you swat a fly, drop it in the tank - you'll be surprised.
Most wild-caught fishes will initially refuse dry or prepared foods, especially flakes. Some may learn to accept them over time, others will not. Some fishes will never accept prepared foods. They may key on the motion of the food, or the color, or the texture.
There are a number of live foods available from most pet stores. The best is Blackworms. These are small worms that are sold in portions. Blackworms must be kept refrigerated or they will quickly spoil. Keep them in a sealed glass jar about 1/4 full of water, where they will form a ball. Rinse the water out under at least every other day under the tap, and the worms should keep for at least a week. An old tablespoon can be used for feeding. I keep the jar out of sight in the produce drawer of the fridge. Worms that escape your fish will take up residence in the gravel in a freshwater tank, but this is not usually a problem, as the fish will root them out. They die in salt water, but wiggle violently for several minutes before they do.
Tubifex worms are similar to Blackworms, and may be kept the same way. Compared to Blackworms, they are smaller and thinner. Tubifex worms must be rinsed every day or they will spoil and die. Of the two types, Blackworms are far superior.
Adult brine shrimp ( Artemia, also known as "Sea Monkeys" ) are another excellent live food. Brine shrimp die quickly in fresh water, but will live for several days in a marine aquarium. Brine shrimp should
be kept cool, but do not need to be refrigerated. Brine shrimp eggs are also available, and can be hatched out in ordinary saltwater. This takes about three days. They make an excellent substitute for plankton. For larger fishes, a range of inexpensive feeder fishes is available, from small guppies to minnows ( "pinkies" ) to goldfish. All are freshwater, and quickly die in saltwater.
Finally, it is often possible to collect your own live foods. At night, simply dipping water with a fine net can bring up a variety of plankton and small shrimps, which are probably the closest thing to a natural diet that you can provide. Small mussels are another excellent natural food. They can be kept live in a marine tank, or frozen. Few fish can crack them open without help, but you can pop them easily with your fingers. For larger fishes, regular old earthworms are an excellent food.
A problem with all types of live food is that you risk introducing disease and parasites into your tank. In particular, I think store-bought worms are a major source of freshwater Ich. This should not be a problem for healthy fishes in a healthy tank.
The most common and treatable fish disease in both freshwater and saltwater is Ich ( or Ick. ) However, although they have similar life cycles and symptoms, the freshwater and saltwater varieties are actually quite different, and caused by entirely different organisms. In both cases, the organism is a parasite, which has three major life stages:
During the feeding stage, the parasite causes small white dots to appear all over the fish. Although they appear first on the fins, by the time this is apparent the parasite have already infested the gills. With a heavy enough infestation, the fish will suffer respiratory and osmotic distress from the tissue damage, eventually resulting in death.
A freshwater Molly with a bad infestation of ich
The ich parasites occur naturally in all waters, and it is likely that all fishes carry a low-level infection. Lethal occurrences of ich in the wild are rare, because of the low probability of any single parasite finding a suitable host during its brief swimming stage. However, in a closed system such as an aquarium, the natural balance between parasite and host that occurs in the wild is tipped heavily in the parasite's favor. Most of the time, in the confines of a even a large lightly-stocked aquarium, many parasites will find hosts. After just a few generations, the parasite population explodes, and overwhelms the fish.
Trophont (phase I) |
Tomont (phase II) |
Theront (phase III) |
| Single-celled adult parasite feeding on fish. This is typically when you'll know that your fish is infected with Ich, as you will see 'grains of salt'. | The trophont enlarges, breaks out of the cyst and falls to the tank bottom. The trophont becomes encapsulated at the tank bottom (a tomont), where it begins to divide internally into hundreds of single-celled parasites. |
Theronts ( swarmers) are free-swimming microscopic parasites, which hatch from tomonts in search of a fish host. One tomont may hatch as many as one thousand theronts. |
| Note: This is the longest phase of the cycle (4 days) as the parasite draws nutrients from your fish. The parasite is not vulnerable to treatment in this encysted state. | Note: This is the shortest part of the lifecycle (1 day) and may give the aquarist the false sense that all is well because of no visible signs of disease. There is a small window of time where the Ich parasite is vulnerable to treatment just before it enters another encysted state. | Note: In this stage (typically 2 days) the parasite is at it's most vulnerable state. The parasite will die within a few days if it does not find a suitable host (a stressed fish). Make sure you have anti-Ich medication in the water at the proper dosage during this stage. |
Only the free-swimming stage of the ich parasite is treatable by usual means. In freshwater, this is a simple matter of dosing with any of the commonly available cures, over a period of several days to several weeks. Most of these involve some kind of blue-green dye, which kills the swimming parasites. The parasites that are already on the fishes are not treatable, but will fall off in time. Likewise, the reproductive cysts are not treatable, until the swimmers hatch out. The life cycle of the parasite can be accelerated by raising the water temperature, although many cold-water fishes cannot tolerate this. Curing freshwater ich is relatively straightforward and easy.
Saltwater or marine ich is a different matter entirely. This is caused by either of two different organisms, both of which are much more resistant to treatment than the freshwater ich parasite. Low-level infections may be retarded by dye or copper treatments, but in truth, neither of these are very effective in curing the disease, and are totally ineffective against a major breakout. An added drawback is that many of the standard marine ich treatments, ineffective though they may be, are deadly to invertebrates such as anemones, and many of them seem to be equally lethal to the fish they are supposed to cure! Copper is the same active ingredient in bottom paint, and in high enough concentrations is lethal to all living things. Even a trace of copper in the water can cause echinoderms ( starfish, urchins, etc ) to simply disintegrate.
Fortunately, most of the local temperate fishes are relatively immune to the disease, far more so than tropical fishes. The best way to avoid marine ich is to avoid its worst carrier, the Spotfin Butterflyfish. Do not keep these fishes - almost nothing can withstand the onslaught of disease that they will inevitably bring into your aquarium. Likewise, do not add any store-bought specimens to a tank - these are often loaded with tropical diseases which will run wild among your native fishes. Another fish which is especially susceptible to Ich is the Naked Goby.
I have never successfully treated a case of what I would call "Butterflyfish Disease". In the end, I have had more than one tank become a total loss, not in the least due to the harmful effects of the "treatments" on the entire system. Most of these so-called medications will upset the biological balance of your aquarium so badly that it will turn into a fetid stinking mess with nothing left alive.
The fastest and easiest way to clean out marine ich and recover a tank like this is to drain it and refill with cool tap water. Don't worry about the chlorine. Make sure to continue running the filters, so that the entire system gets a good freshwater flush. The marine ich parasites cannot survive freshwater immersion ( nor can they survive drying ), and all stages of the parasite will be killed. In freshwater, they swell up and literally explode. After a day, drain and refill the tank with saltwater. The beneficial nitrifying bacteria in the gravel and the filter will largely survive this treatment, and the tank will be usable again in several days. Stock it lightly at first, as you would a new tank.
In general, the aquarium trade makes a lot of money selling "cures", most of which do not work, and many of which are more harmful than helpful. While in theory many of these should work, in practice, the end result of most chemical treatments is usually the same - a dead tank. The truth is, apart from ich, you have very little chance of even correctly diagnosing a fish disease, and chances are that by the time you have noticed it, it is already too late. Throwing chemicals and antibiotics at an unknown malady is more likely to do harm than good. This is especially true of antibiotics. A far better cure for most minor diseases, including low-level outbreaks of marine ich, is to improve the water quality and reduce the parasite population through water changes.
A non-chemical treatment that is effective on marine ich and other parasites is UV ( ultraviolet light ) sterilization, which will destroy the free-swimming parasites before they can get to the fish. This is not 100% effective, but may reduce the parasite population to a low enough level that the more resistant fishes recover on their own. Weaker fishes should be released, they will have a better chance of recovering in the wild, and in any case they will no longer be able to reinfect the others.
In the end, prevention is far better than cure. The best prevention for all types of fish diseases is to maintain healthy water conditions. Don't overcrowd, perform regular water changes, and avoid species that are known to be disease-prone.
I make no claim as to the accuracy, validity, or appropriateness of any information found in this website. I will not be responsible for the consequences of any action that is based upon information found here. Scuba diving is an adventure sport, and as always, you alone are responsible for your own safety and well being.
Copyright © 1996-2008 Rich Galiano
unless otherwise noted
