How to prevent and treat Malawi bloat in your cichlids

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Malawi Bloat is a term that strikes fear into the hearts of cichlid keepers all over the world. Yes, this is a serious and often fatal illness but you don’t have to lose hope, if caught early enough, treatment is often possible. In this article, we’ll cover the identification, causes, and treatment of this illness so that you know what to look out for, and what to do if it affects your fish.

Overview of Malawi Bloat

NameMalawi Bloat
Common TreatmentsMetronidazole, Epsom salt
CausesHexmitia and secondary bacterial infections. Poor diet and stress
Common SymptomsLoss of appetite/spitting out food, Hiding, Stringy white feces, Bloated belly/Dropsy, Lifted scales

What is Malawi Bloat In Fish?

Malawi Bloat is a pretty common, but serious illness that mostly affects African cichlids from East African lakes like Lake Malawi and Lake Tanganyika. This problem isn’t limited to African species from the rift lakes, however, and other tropical fish can also be affected.

Malawi bloat is a disease of the fish’s digestive system that causes swelling and eventually death after a matter of days if left untreated.

What Does Bloat Look Like?

In its early stages, Malawi bloat causes some behavioral changes like hiding and a lack of appetite in your cichlid. You might also see, long, stringy white feces hanging from your fish.

The physical appearance of Malawi cichlid Bloat in its more advanced stages is a bloated/swollen belly that looks like dropsy. The scales of the fish might also lift up, and there might be red markings around its vent. Here is an example of a fish that is recovering from bloat. This was the best video I could find without scaring folks. It’s from Universal Cichlids’ YouTube channel.

Malawi Bloat isn’t the only cause of a swollen abdomen in cichlids, however, so don’t panic too soon. Often, your fish may simply be overfed or constipated. If a bloated cichlid is still eating, you’re in luck, it is highly unlikely to have Malawi Bloat.

What Causes Bloat?

The general consensus on the medical cause of Malawi Bloat is an increase in numbers of a protozoan parasite in the gut of fish. These protozoan parasites, or flagellates as they are also known, are tiny creatures that live in all fish and don’t usually cause any serious harm. The culprit that is to blame for bloat is called Hexmitia. I’ll leave a scholarly article at the bottom of this post that discusses Hexmitia more in detail.

There is also some reason to believe that Malawi Bloat can progress into a bacterial infection, although this is likely to be a result of the increased parasite load that is already causing illness. Some keepers believe the disease is caused primarily by a bacterial infection like dropsy.

The fact of the matter is that there isn’t (at the time of writing anyway) a universally accepted cause.

You may be wondering why parasites and bacteria that occur naturally in your fish could become such a huge problem all of a sudden, and the simple answer is stress. When your fish is under stress, its immune system becomes compromised and parasites and bacteria that are usually kept in check start to multiply.

There are many possible causes of stress, or stressors, for your fish. Some of the most important stressors are:

Poor Diet

Feeding high protein diets to herbivorous fish is thought to be a possible cause of Malawi Bloat. Whether it can be directly linked to the disease is not known for sure, but a poor diet is definitely a stressor in any fish.

Always research the natural diet of your fish to find out if they are herbivorous, carnivorous, or omnivorous. Remember, if they don’t eat meat in the wild, it shouldn’t be on top of the menu in your tanks. Though this is a highly debated topic regarding protein, the real underlining matter is how much roughage the fish is eating. This can come in the form of protein, such as the chitin from arthropods like brine shrimp and krill.

I know it can be difficult to work with frozen food, so I can point you to a pellet that works. This fish food is crated by Ron Demers, an African Cichlid breeder with over 25 years experience. He developed his food line to have the balance of proteins, veggies, and minerals. He removes all the fillers that you would get from lower quality foods. This is about as good as you can get with pellet food.

Great Balanced Food
Ron's Cichlid Food

Ron is an African Cichlid breeder with over 25 years in experience who created a line of food that is well balanced. A great option when you can't use frozen foods.

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Roughage, like with humans are needed to maintain a healthy digestive system. It would make sense you would want this to for your African cichlids. Manufactured foods like flake food will not contain the essential roughage. You will want to seek out more natural and raw foods.

Poor Water Quality

This is a big one folks, and there are quite a few possible causes of poor water conditions in your aquarium.

Inadequate filtration often causes poor water quality in fish tanks. A good filter in a properly stocked and cycled aquarium should keep your ammonia, nitrite, and nitrate levels in check. A filter that can process 4 to 6 times the volume of your aquarium is generally advised. Cichlids are larger, active, and tough on a bioload. One should be looking at upgrading their filtration with quality biological media and filters with large media capacity like canister filters.

Even with the right filter, you should be careful not to feed too much fish food and clean your tank regularly. Get into the habit of performing routine partial water change to keep your water conditions safe.

Water Parameters

Aquarium water chemistry is very important to keeping healthy, happy cichlids and you should always strive to keep parameters like pH, GH, and KH as close to your fish’s ideal values as possible. Be sure to use a water conditioner when adding new water to your aquarium during a water change and use aquarium salt as little as possible as this is thought to be a possible cause of Malawi Bloat. Keep your nitrates at management levels to also reduce the stress on your fish and monitor with aquarium test kits.

Other parameters like incorrect water temperature, low oxygen levels, too much water flow, and unnatural and irregular lighting can also be very stressful for your aquarium fish.


Stocking your tank with incompatible species can be a major source of stress and aggression for your fish. Cichlids tend to be territorial and many species are very aggressive in defending their territories, often injuring or even killing other fish in the tank. This aggression is a major cause of stress.

When stocking your fish tank, make sure that all the fish in the tank are comfortable in the same water parameters and make sure that the species you choose are compatible. With many cichlids, you will need to get the ratio of males and females right to avoid aggression.

Tank Layout

The layout of your tank can also have a pretty big effect on the well-being of your aquarium fish. Species that prefer to live in open water can easily become stressed in a crowded tank for example, or a bare tank without hiding spaces can also cause significant stress to fish that live in very rocky areas with a lot of structure.

Any one of these stressors could result in complications for your fish, and often the problem can be made even worse by a combination of factors. As a rule, always do your best to limit all of the stressors mentioned here. It could go a long way towards preventing most of the problems you might pick up in your tanks.

Identification And Symptoms

In the initial stages of Malawi cichlid Bloat, the signs that you have sick fish are mostly changes in behavior like:

  • Lack of appetite
  • Spitting out food
  • reduced activity
  • Increased breathing rate

One of the tell-tale symptoms is the feces of the fish will be clear or white-ish and stringy, remaining attached for long periods of time. Normal feces can also occur in long strands but it will be thicker and darker in color. Fish may also struggle to stay right-side-up and may have problems with buoyancy.

If you notice one or more of these symptoms in your aquarium fish, it’s time to act. By the time the disease becomes physically visible, sadly it’s often too late. When the disease becomes advanced, the gut area will swell up, often massively. This is where the term bloat comes from.

Other common physical signs of Malawi Bloat are:

  • Ulcers on the skin
  • Red marks around the vent
  • Lifted scales


If you’ve spotted some of the symptoms of Malawi Bloat in your cichlids, act immediately by moving the infected fish to a hospital tank for treatment. If more than one individual is affected, you may wish to treat the entire tank instead.

Do a water test to check all parameters and look for any sign of other stressors in the aquarium. Try to fix any problems you find and go ahead and perform a large water change of up to 40% or so.


In the past, aquarists often made use of a product known as Mardel Clout for the treatment of Malawi Bloat. Unfortunately, this product has been discontinued and is no longer available.

Currently, the most popular medicine for the treatment of Malawi cichlid bloat is Metronidazole, commonly known as Metro. This is an antibiotic that works on certain bacterial and parasitic protozoan infections.

This drug is commonly sold as Metroplex, Flagyl, or Octozin. It is also used in the treatment of another common parasite-caused illness of freshwater aquarium fish known as hole in the head, or head and lateral line erosion.

Metronidazole can be administered in two ways, orally, or dosed in the water column. Of course, a sick fish affected by Malawi bloat will not eat and so you’re probably going to need to administer treatment through the water column.

At the same time, it is a good idea to feed your other fish a medicated food to prevent any more cases or treat them before they get serious. Again, Metronidazole-soaked food is the best option, even if the other fishes aren’t showing any symptoms.

A great method for preparing medicated food is to use a product like Seachem Metroplex combined with Seachem Focus, which will bind the metroplex with the food and minimize it leaching out in the water. Another great combo is General Cure and Focus.

Seachem Metronidazole

Seachem Metro is great to use with focus as a medicated food supplement option

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To prepare one tablespoon of medicated fish food, Mix one scoop of Metroplex and one scoop of Focus with a little water. Soak your frozen or pellet fish food in the mixture for at least 15 minutes and store this food in a clean container. This medicated fish food can be kept refrigerated or frozen and it should be fed to your fish until any affected fish have recovered, or for up to 3 weeks. Move your affected fish to a hospital tank to keep the disease from spreading and to keep the fish from getting bullied.

Other Treatments

You can dissolve Epsom salt into your fish tank water to further assist your fish by decreasing bloating in the digestive system. Use about 1 tablespoon of Epsom salts per 5 gallons of water in your tank but add it gradually to prevent shock.

You can also feed your fish peas at this time, which should be boiled lightly and allowed to cool. Peas are known to be a natural laxative for fish. During treatment, keep your lights low because this has a calming effect on your fish.

If you’ve been successful in your treatment, the symptoms like swelling should subside and the scales should flatten out. Once your fishes have regained their normal, healthy appetite and begin to defecate normally again, you know you’re back on track.

Another great medication that used to be available was Mardel’s Clout. Unfortunately, it has been banned due to having cancer causing agents. Hoping there can be a replacement in the market eventually as this medication used to be the go to when it came to fighting this disease.


How do you fix bloat?

The advised treatment for Malawi cichlid bloat is with the use of an antibiotic known as Metronidazole. This can be done after moving the affected fish to a hospital tank or you can medicate all of the fish if there is more than one case.

You should try to find the root of the problem if possible and perform a partial water change. It is also helpful to dose the water with Epsom salt.

Is bloat contagious in fish?

It is unclear as to whether this disease is contagious but it definitely can affect several individuals in the tank at the same time. This could be explained by all your fish being exposed to the same stressors in their environment at the same, or maybe because of an increased load of bacteria and parasites in the system.

While there isn’t a clear answer at this time, you are recommended to treat all of your fish with Metronidazole soaked fish food, even if they don’t show any symptoms.

How do you treat dropsy in cichlids?

Dropsy is a symptom of various conditions (including Malawi Bloat) that is seen as swelling of the abdomen. The best treatment for this symptom is to medicate with a product containing Metronidazole, dose Epsom salt, and feed boiled peas, as you would with Malawi Bloat.

Will this type of bloat go away?

Unfortunately, Malawi Bloat will not clear up without treatment. You should act quickly if you identify this disease in your cichlids because once the condition progresses to the point where symptoms are visible, it is often too late.

How do you stop cichlids from bloating?

By far the best way to stop cichlids from bloating is to keep them in a healthy environment that is specifically designed for their needs and to feed them correctly. In the case that Malawi cichlid bloat does occur, don’t beat yourself up about it, it is a common condition that even experienced keepers struggle with from time to time.

The key is to keep an eye on your fish and their behavior and catch the problem early. Once diagnosed, treat the fish with a product containing Metronidazole and dose the water with Epsom salt.

References & Further Reading

When it comes to talking about fish diseases, we should use cited scientific articles when available. Here are several to help educate you on bloat and parasites.

University of Florida – Management of Hexamita in Ornamental Cichlids

Klinger, R. & Francis-Floyd, R. Introduction To Freshwater Fish Parasites. University Of Florida, IFAS Extension

Francis-Floyd, R. Stress-Its Role In Fish Disease. University Of Florida, IFAS Extension


Malawi Bloat is a serious disease that often affects African cichlids and other aquarium fish. It’s important to remember that bloat is very scary and can happen at any time. This article has provided you with a number of tips on how to prevent it as well, but if your fish does get bloated there are some medications that will be effective in treating the disease. We encourage everyone who reads this blog post to leave us their thoughts below about what they think causes malawi bloat or anything else they might want more information on. Happy reading!


  1. Hi Mark. Such an informative page here, thank you.

    We live in Denmark, where a change in the law means that we are no longer allowed to buy medicine for fish over the counter. So we will order online.

    How do you recommend treating fish with flagellates and Malawi Bloat?

    We have lost 14 fish in 3 months.

    First a bunch of Golden Spec got sick, with starved stomachs and the black around the eyes enlarged, only the pupil.

    Now it seems that more people are getting sick but with symptoms of Malawi Bloat. Several of our fish have been observed with the characteristic thin white feces.
    They are shy and seem lethargic. We had a fish with a collapsed pectoral fin and a small pouching on the same fin. We found it dead, with a small hole by the fin a few days later.

    Information for you:
    We have a 900 liter aquarium with a background filter.
    A total of about 60 fish, all Malawi.

    The aquarium was started from scratch 3 months ago following all correct instructions and a third of the water is still changed once a week.
    We also measure water quality in connection with water changes

    We have Demansoni, Golden, Pearlmut, Red Zebra, Rusty, Cobolt Blue, Alongatus and Clown Loach.
    And 2 Ansistrus.

    Do you have any suggestions for treatment? And is processing different when we have a background filter?

    Kind regeres

    Kenneth and Miia

    • Hi Miia. For Malawi bloat metronidazole will be the best. A diet change is going to be necessary going forward. You will need to make sure the food you feed has chitin protein fibers. This will prevent bloat from occuring. This lack of chitin is often the cause of bloat when it is not caused by a parasite.

      Bind metro with a product like seachem focus or use general cure plus focus. Mix with food. Use garlic if necessary to encourage your fish to eat.

      With focus – the product will be safe to use in a display tank.

  2. Hey Mark just read your article on Malawi bloat.. I keep only demasoni in a 4ft 220ltr tank, roughly have 20 of all sizes, have black – specialty African cichlid substrate, alot of Texas holey rock, and Java fern in the tank.. Had this setup for a little on two years slowly building numbers. They seem healthy, are vibrant in colour, eat properly and even had alot of natural breeding with 3-4 young managing to survive in the main tank every time. I feed high quality vege flakes and crisps with once a week peas, brocc, or zucchini. Water parameters are fine, have a canister filter and in tank one for air.. My concern has always been they are ultra skittish and hide alot never just swimming/hovering like crowds of demasoni I have seen in other videos / pics. Thoughts?

    • Hi Kendall. Is there any aggression or overcrowding in the tank? Are any of your cichlids actively breeding? I shows like you may have more fish than you original had and they are adults now.

  3. Hi Mark, it is me again concerning my cichlid I e mailed you about several weeks ago. He is still hanging in there. I am no longer sure this is bloat. I have been treating him constantly with Epsom salt and MetroPlex and nothing helps. I have him in a large glass jar in the aquarium and treating him that way because when he is out he cannot swim. He lays on his side in one place for a long time. Sometimes you would think he is dead. Every couple of days I let him out in the aquarium over night but he ends up just laying on the bottom. However, he has gotten more strength because I see him try very hard to right himself by moving his tail fin a lot. But he tires himself out and just lays still and he cannot right himself! I have never had an experience like this with a fish. I have been very careful with the amount of MetroPlex I administer to him and wondering should I increase it or use another medication. His strength is there and his will but poor little fella can’t right himself.

  4. Thank you, Mark, for answering my message re. my sick Convict Cichlid. Believe it or not this poor fish is still hanging on, but not looking any better. All my water test kits are old since I haven’t used them in years and should get new, but, I feel by the time I would spend $$ on this problem I will have a dead fish on my hands anyway, I’ve been down this road before with angels. I did get a new bottle of methblu not realizing I should have gotten metroplex or the like. I am not sending any pics because the water is blue from the methblu and probably will not take good. I feel maybe I should take the fish out instead of letting it linger like this, but I do not have the heart!

    • I’m sorry to hear about that Bonnie. Is your fish eating at this point? If not, considering enthusia might be the best case. You can do it with clove oil. I haven’t written about it, but I do plan on it in the future

  5. I have on old Raphael cat fish and one blue with black stripes “Convict” Cichlid in a 75 gallon tank. The Cichlid I have for about 2 years. Aquarium has lots of rocks and one large piece of driftwood and one good hiding place for the Cichlid. Just yesterday I noticed the Cichlid laying in the corner on his side but still alive. I quickly did a water change of approx. half and am treating with Epsom Salt and Methyblu. I am keeping the light off and raised the temp. (hasn’t finished increasing yet.) I keep it at 74 degrees normally. The Raphael looks OK but the Cichlid is on his side this morning but still alive. More than this I don’t know how to help him.


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