Yesterday, I really knew very little about a malady that African Lake Cichlids get called Malawi Bloat. Probably because I really don't keep Mbuna or other African Lake fish. But then I ran across an article by Marc Elieson that seemed to sum up the malady pretty well. So I thought I would rewrite the article infusing some of what I learned from it and also what I gathered from a conversation with expert African Cichlid breeder Robert Stagno.

Now some of you reading this and having experienced the Bloat might be saying to yourselves, "Yeah right, easily avoided-my foot!" Both Marc and Robert believe that "Malawi Bloat" can quite easily be avoided. Their credentials for this statement and article are simply the combined wisdom of their own experiences as well as mine.

I should begin by saying that "Malawi Bloat" does not only affect fishes from Lake Malawi but also those from Lake Victoria and especially Lake Tanganyika. The first symptom is a loss of appetite. If you do not take immediate action at this point, other characteristics follow and you will most likely lose your fish. These secondary characteristics include abnormal swelling of the abdomen (hence the name-bloat), an increased respiratory rate, reclusive ness, white streaky feces, and sitting on the bottom of the tank or lingering at the surface. Red marks around your fish's anus or skin ulcerations might also be apparent.

If you see these secondary symptoms, probably at this point, it will be way too late to rescue your fish because extensive damage has already occurred to the fish's liver, kidneys, and/or swim bladder. Death typically results within 24-72 hours after the onset of these secondary symptoms, although they have seen some fish hang on for more than a week in this condition. Needless to say, when Marc tried to rescue them, they already had these secondary symptoms, and it was too late; they didn't respond to any of the therapies Marc tried.
Marc has found from his personal experience that it is atypical for more than one fish to be ill with this condition at a time, but fish will tend to die off at intervals of a week or so.
Three of the main causes for "Malawi Bloat" have been identified:
1) The addition of large amounts of salt (NaCl) with the intent of simulating a more natural habitat. True, the rift lakes of Africa are alkaline and have very hard water (pH 8.0-8.9, and a General Hardness between 200-400 ppm), but common salt will not alkalinize your tank. What makes water "hard" is a combination of dissolved calcium and magnesium. If you have soft water and need to raise the pH/hardness of your water, I suggest you use SeaChem's Cichlid Salt, and/or the use of crushed coral as a substrate. Rocks, like limestone, are also helpful in raising the pH of aquarium water, but because minerals don't stay suspended in water for long, it's important to do frequent water changes. We would discourage you from using any wood, as it will only serve to lower the pH of your water, even if its effects are minimal.

2) Long term exposure to poor water conditions. This can be due to infrequent water changes, not enough aeration (for the denitrifying bacteria), and overfeeding. All three of these factors leads to elevated nitrate levels in the water. Fish are very good at fighting off disease on their own, but when exposed to poor water conditions over a long period of time, they become stressed and their immune system does not function at its optimal level (just as with humans!). What actually causes the diseased condition seems to be a parasite that becomes invasive when the fish is stressed. There is some disagreement as to whether it is actually a protozoan or bacterium that causes the intestinal tract infection.
3) Improper diet. Herbivorous Cichlids have long intestinal tracts, and therefore, it is quite common for them to have intestinal problems. The decomposition of improperly digested, or improperly excreted foods can irritate the intestinal wall, and stress the fish, giving the invasive parasite a foothold. This can often come about when a primarily herbivorous, algae scraping cichlid (like Tropheus spp.) is fed high protein foods such as bloodworms, or pellet and flake foods containing large quantities of fish meal. In light of this information, and experience, it is important to avoid certain foods, and to go light on others.
FOODS TO AVOID:
Tubifex. This is a thin, red worm that lives in mud of rivers, and is usually collected from polluted rivers. By feeding Tubifex to your fish, you are exposing them to the diseases these worms may be carrying.
Red blood worms I have fed bloodworms to my fish without any known incidents; however, I know some authorities out there caution against them. Note, however, that I feed with these very light--only what they can consume in 30 seconds.
Beef Heart. Fishes are unable to utilize fat from warm-blooded animals for energy use. As a result, these fats build up in the liver, and over time will result in degeneration of their liver. For this reason, meat from any warm-blooded animal, and especially beef heart, is bad for your fishes.
Any food advertised for American Cichlids. These foods are very dangerous for African Cichlids because the two classes of fish have such different dietary needs.
FOODS TO GO LIGHT ON:
Pelleted food. Pellets tend to swell a great deal after they have been put in water; therefore, you will want to soak them before feeding them to your fish. You don't want them to swell inside your fish's abdomen because they could seriously distend, irritate, or cause their digestive tract to explode. Pellets have been the culprit in most of the deaths I have had, due to "Malawi Bloat."
Flake food. You should not feed your cichlids more than they can consume in two minutes, not five! I like to feed my cichlids several times a day, so that they aren't gorging themselves on large amounts of food at any one time. So, I only feed them what they can consume in 30 seconds. This is more natural, because in the wild, cichlids are nibbling on algae, plankton, or Artemia (a.k.a. brine shrimp) through out the day. This also helps to prevent digestive problems. Remember, cichlids have long intestinal tracts.
Frozen food. Any food that is high in protein, such as krill, brine shrimp, daphnia, plankton, bloodworms, and micro-worms should be used sparingly. And for herbivorous fish, like those from Lake Tanganyika, they should not be used at all. I use these foods only as supplements to my cichlids' main diet of Spirulina flake food. Flake food is ideal because it is quickly digested, and does not clog their intestines. Spirulina is also very nutritious and high in protein. When feeding frozen foods, it's important to only feed it to your fishes once it has completely defrosted and been broken up because an aggressive cichlid will more than likely snatch the whole cube up and wake up the next morning with a bad case of Bloat. I defrost a chunk of frozen food in a cup of hot water, and use a stick to break it up. When I use these frozen foods, I do so only once or twice a week, and no more than they can consume in 30 seconds. Because cichlids are avaricious (e.g., borderline obnoxious) eaters, they can consume a great deal of food in 30 seconds or less.
The safest foods for mbuna (non haps) cichlids are those that are predominantly vegetable based, such as peas, zucchini, and romaine lettuce. If you freeze these vegetables and then thaw them, they will soften up and can be consumed quite readily.
TREATMENT:
Once you notice that your fish has lost an appetite for food (and is not just holding fry in her buccal cavity), you should remove it and begin treatment immediately. There are two effective treatments for Bloat that Marc knows of. The first and most common is Emtryl (Metronidazole), and the second is Clout.
Robert on the other hand uses a Drug called Paragon II, which contains Metronidazole, Neomycin Sulfate, NaCl, Furazolidone and Naladixic acids.
The treatment should be preceded by a 30% water change (in an effort to improve water conditions) and increased aeration, followed up with a 50% water change. It is also a good idea to remove any filters you may be using. For even though these drugs claim they don't harm denitrifying bacteria, they might and also the filter medium quite possibly could remove the medication before it has time to work. The initial 30% water change is not necessary if this is a hospital tank that has not previously been used. The water change is important partially because you won't be performing water changes for the duration of treatment. I recommend combining these two drugs, dipping with Clout (2x/day with 4x concentrated Clout for 30 min.) and using Metronidazole in the hospital tank until the fish has been cured. You will know when this occurs because the fish will regain its appetite.

A word of caution about Clout: Clout is a very strong drug and can cause a lot of stress to your fish. Metronidazole will typically work well by itself; however, Clout is good for "dips." Clout also turns the water blue and will often stain the silicon in your tank blue, as well as any airline tubing you may have. While it has proven effective, many wish they had known what it was going to do to their tank. And so, I am just warning you. Also, it is a good idea not to turn on your hood lights while administering these two drugs, as the UV rays will disable some of the active chemicals in them, the byproducts of which are toxic to fish and humans.

Again I would like to thank Marc Elieson for letting me borrow so heavily from his article and Robert Stagno for helping me put the finishing touches on this disease profile.