Flowerhorn Bloated Stomach – Causes and Treatments

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The flowerhorn is one of the most exotic-looking fish you can get since nothing beats this aquatic version of a red Megamind in terms of looks.

Whether you’re acquainted with the flowerhorn or not, here are some fast facts before diving into today’s topic:

  • This is a cichlid, suspected to be the crossbreeding result between a Blood Parrot Cichlid and a Red Devil Cichlid; which explains much of its appearance
  • The flowerhorn can grow up to 10 inches in optimal water conditions and given a proper diet
  • The ideal water parameters include a 70-gallon tank, 78-84 °F temperature, and 8-20 dGH water hardness
  • Flowerhorns don’t exist in the wild since they are the product of selective breeding
  • Flowerhorns have been released in the wild and have adapted quickly, soon becoming an invasive species; as a result, they rank as pests in some parts of the Globe
  • The fish’s distinct head structure is called a nuchal hump and can vary in size and shape between different specimens
  • Some flowerhorn males don’t have the trademark hump
  • Flowerhorns are egg layers, omnivorous, and display the distinct cichlid aggression that makes them incompatible for community tanks, with minor exceptions
  • Flowerhorns are generally easy to care for, even fit for beginners

Now that we have the basics down let’s discuss today’s topic: flowerhorn bloating issues. What causes them to become bloated, and how should you address the problem?

Flowerhorn Bloated Belly – Causes and Treatment

Figuring out the cause for their condition is key for preventing the problem from aggravating.

Let’s assess 6 of the most widespread causes for bloating in flowerhorn:


Dropsy isn’t a condition per se but rather a symptom. The term generally refers to fluid accumulation in the body, including the abdomen, leading to a bloated appearance.

The disorder’s triggers may vary wildly, going from benign to severe, capable of killing your fish fast.

Some of the potential causes include liver dysfunction, bacterial and parasitic infections, and even organ infections due to a variety of pathogens and disorders. The treatment will differ based on the disease’s underlying factors.

Some relevant symptoms include:

  • Inflated abdomen, somethings to unnatural proportions
  • Bulging eyes
  • Body ulcers that vary in size, spread, and localization
  • White or pale and stringy feces
  • Visible changes in appetite
  • Lethargic behavior and many others

Depending on its triggering factors, dropsy can be deadly, so immediate treatment is key to helping your flowerhorn recover quickly.

How to Treat Dropsy?

Once you’ve determined the condition’s underlying triggers, I suggest the following:

  • Quarantine the sick fish – This will protect any other tank mate if any available. If not, quarantining the flowerhorn will protect the tank’s biofilm in case you will need to use antibiotics or any other medication. The hospital tank should provide similar environmental conditions and water parameters to the main tank.
  • Ensure optimal water parameters – You may need to perform water changes of 10-15% and remove fish waste and food leftovers daily to keep the flowerhorn’s tank clean and stable. This will help the fish recover faster, minimizing the disorder’s symptoms and preventing any complications.
  • Use antibiotics – Antibiotics will address any parasitic and bacterial infections, as well as secondary infections resulting from them. I recommend not using antibiotics in the main tank, as these could disrupt the aquarium’s biofilm and change the water’s chemical composition. Always have a hospital tank available for situations just like these.
  • Offer a balanced and nutritious diet – Many people tend to ignore their flowerhorn’s diet consistency and nutritional value with time. This is typical for all fish owners in general since they tend to take their fish for granted after a while. This is one of those cases where such an attitude could have devastating consequences. Your flowerhorn will require a balanced and optimized diet during the treatment to aid in its recovery and strengthen its organism.

When dealing with dropsy, remember that early treatment is crucial to prevent the disorder from aggravating. The condition may even be contagious, depending on its causes. So, don’t treat it lightly. Pun intended.

Swim Bladder Disorder

Just like dropsy, the swim bladder disorder isn’t a disease on its own but rather a symptom of an underlying condition. Let’s consider how the swim bladder works to understand what’s going on.

This organ is located above the fish’s stomach and digestive system, and it’s quite long and bulky. It typically stretches throughout the fish’s internal digestive cavity.

This organ is hollow since its purpose is to take in air and support the fish’s buoyancy. This is where the problem arrives. If the fish’s organs or stomach grow in size, either due to disease-related inflammation, infections, or other causes, the swim bladder won’t have enough room to inflate anymore.

So, the fish will experience buoyancy issues which, depending on the species, can be deadly. Because fish need to swim to be able to breathe, see.

Some of the immediate signs that your flowerhorn is experiencing swim bladder problems include:

  • Inability to remain afloat and sinking to the bottom of the tank
  • Spending more time near the substrate
  • Difficulties in maintaining posture as the fish constantly turns on its side or upside down
  • Curved spine as the inflated stomach or organs pushes the belly down
  • Enlarged belly, depending on the condition’s causes
  • Lack of appetite

When it comes to the causes, we have:

  • Overfeeding – This is a common problem among fish owners due to their predilection towards providing their fish with more food than necessary. The issue here is that tank fish, and fish in general, tend to eat as much food as available. This is part of their biological setup, conditioned by endless generations living in harsh environmental conditions with scarce food. Placing the fish in a safe setting with an abundance of food won’t change its genetically-inherited behavior. So, you need to control its diet and meals to prevent overfeeding. Otherwise, eating more than necessary will cause the fish severe digestive problems, from constipation to compaction, which can be deadly. But, before dying, your flowerhorn will experience swim bladder problems which, fortunately, is reversible.
  • Enlarged organs – These are generally the result of fat accumulation, kidney problems, internal parasites, or other disorders that can trigger such an effect, including cysts and tumors. Assessing your flowerhorn’s condition accurately is key to ensuring a proper diagnosis.
  • Improper tank temperature – Flowerhorns thrive in higher temperatures that fall into the tropical range, around 78 to 85 F. What many novice aquarists fail to realize is that the water’s temperature is not only meant to ensure the fish’s comfort but influences its biological functioning as well. For instance, the flowerhorn requires higher environmental temperatures to boost its metabolism, which, in turn, accelerates the digestive process. If the water temperature drops below the recommended limit, the fish’s digestive system will lose some of its effectiveness, potentially causing constipation or compaction. Which will affect the swim bladder as a result.
  • Birth defects – Some fish may also experience genetically-related swim bladder problems, but these are unlikely to occur in mature fish. If your fish’s condition is genetic, the signs should be visible early, as the fish is still a juvenile.

Once you’ve determined the condition’s causes, the treatment should follow shortly to prevent the disorder from aggravating.

How to Treat Swim Bladder Disease?

  • Put the flowerhorn on fasting mode – Don’t worry, nothing bad will happen to your fish if you deprive it of food for 2-3 days. As a matter of fact, this could save its life if the fish shows signs of constipation. The fasting period allows its digestive system to catch on, process the food, and eliminate the waste uninhibited. I recommend increasing the tank’s temperature slightly during this time, preferably around 80-81 F, depending on your flowerhorn’s comfort level. This will accelerate the fish’s metabolism and send the digestive system into overdrive.
  • Boiled and skinned peas – This is a typical anti-constipation recommendation since it contains a lot of fiber. You should only offer boiled and skin peas after the fasting period have completed. The extra fibers will cleanse the fish’s digestive tract, eliminating any residual matter than may have hardened and become stuck in the intestine.
  • Antibiotics – These are only necessary if you’ve identified a parasitic or bacterial infection responsible for your fish’s swim bladder problems. However, I recommend quarantining the fish before the treatment, even if there are no other tank inhabitants to account for. Relocating the fish into a hospital tank will protect the main tank’s biofilm since antibiotics will kill all bacterial life forms indiscriminately, including the beneficial ones. That being said, you should discuss with a veterinarian which antibiotic to use. Not all of them are effective against the same pathogens, while others won’t even affect the tank’s biofilm.

Your flowerhorn should recover fast, provided the treatment is administered soon, and the disorder doesn’t progress.


This is a common condition among fish in general, and it’s not typically that dangerous. The problem is if it becomes chronic or devolves into compaction, which is far more severe.

The most obvious sign is bloating, as the fish consumes more food than it can process. Another is the refusal to eat, despite not displaying any other symptoms that may suggest a different condition.

If your fish doesn’t showcase skin lesions, gill inflammation, or any skin growths, the bloating is almost definitely constipation-related.

But you should always assess the situation more in-depth to make sure you’ve diagnosed the problem correctly.

How to Treat Constipation?

Fasting. This is the first step towards addressing constipation accurately. Allowing your fish to fast for a couple of days will permit its digestive system to address the waste buildup.

If your fish has developed compaction, the process may last slightly longer. In that case, you should always provide your flowerhorn with boiled peas since it aids in evacuation.

Constipation isn’t too difficult to treat, provided you act before it becomes more severe. As a plus, increase the tank’s temperature slightly during the treatment.

This will speed up the digestive process, helping the fish eliminate the food easier.

Carrying Eggs

In some cases, your fish’s bloating is nothing more than a sign of a gravid female. This is even more obvious if the female doesn’t display any other sign of illness.

If the flowerhorn female is pregnant, it will display specific behavior like:

  • Growing belly over several weeks
  • Increase in food appetite, then lack appetite when getting ready to deliver
  • Some strains of flowerhorn display changes in eye color close to delivery
  • Increased aggression and hiding behavior, as the female is looking for a fitting spot to lay the eggs

If your female flowerhorn is gravid, there’s not much you can do about it except provide adequate conditions for reproduction. You should also consider that flowerhorns lay eggs monthly, capable of producing several hundred to 1,000 eggs during each phase.

Given that the female will lay all the eggs within a period of 3-4 days, providing the right environmental conditions is key during that time. Increase the water temperature slightly since this will signal the female that the time is right.

Bacterial Infection

Bacterial infections won’t always display the same symptoms. Some fish may experience dropsy, including an inflated abdomen and protruding eyes, while others may also showcase skin lesions and other specific signs. It generally depends on the pathogen and how it affects the fish.

Some relevant symptoms that occur in most cases include:

  • Pale gills
  • Red and inflated anus or cloaca
  • White and stringy feces
  • Bulging eyes, sometimes with signs of irritation and tissue inflammation
  • Body ulcers varying in size and placement
  • Skin redness and displaced scales, standing out in an unusual manner
  • Behavioral changes, including increased aggression, lethargy, hiding near the substrate, etc.

The causes may be multiple. Some bacterial infections occur due to infected injuries, allowing the pathogen to get inside the fish’s body. Others are triggered by foul water conditions, leading to a generalized overgrowth of bacterial organisms in the fish’s environment.

It’s also worth noting that some flowerhorns display weaker immune systems, causing them to be more vulnerable to infections and diseases.

How to Treat Bacterial Infections?

The treatment should follow a specific setup, no matter the symptoms your flowerhorn is experiencing, so long as there are bacteria involved:

  • Quarantine the victim – You can’t afford to skip this phase, whether you have multiple flowerhorns in the same tank or only one. Quarantine is necessary since the treatment will include using specific medications and antibiotics that could disrupt the tank’s beneficial bacteria. It also allows you to monitor your fish closely during the treatment to ensure the best outcome.
  • Speak to a specialist – When it comes to bacterial infections, it’s almost impossible to identify the causative agent. Most bacteria and parasitic pathogens will display similar symptoms, so you can’t really tell which treatment will work best. I advise consulting a pro vet to learn how to tackle the disorder effectively.
  • Keep the water in peak condition – Perform water changes daily, remove any fish waste and residual food, and monitor water parameters constantly. These actions are essential for providing your flowerhorn with a stable and clean environment for a smooth recovery experience. It will also minimize the risk of secondary infections and complications due to lack of tank hygiene.
  • Antibiotic use – Once you’ve determined the right medication necessary, you can begin the treatment while monitoring your fish 24/7. This means you can’t sleep for the entire duration of the treatment, which could go on for several weeks. That’s obviously a joke.
  • Add salt to the water – This is a good method of aiding in the healing process. Adding salt to your hospital tank will improve your fish’s gill activity, promote the production of slime coating, promote tissue regeneration, and decreases the risk of osmotic stress. Salt can also be effective against certain pathogens that might infect your flowerhorn. How much salt to use is debatable. Typically, you should use around 1 teaspoon per 4-5 gallons of water, but you should rather discuss it with a pro vet about it. Not all fish can withstand the same water salt content, which remains true among different flowerhorn strains.

As with all bacterial and parasitic infections, early treatment is key to increasing the chances of successful recovery.

The longer you postpone the treatment, the higher the chances for irreversible damages and for the pathogens to spread to other tank inhabitants as well.


Tumors are extremely rare, especially those large enough to cause severe bloating. If they’re cancerous in nature, there’s nothing much you can do for your flowerhorn.

Euthanasia is the only solution in that case, not because the tumor is contagious, because it’s not, but because it will save the fish of a lot of suffering. And the outcome is always death, no matter what measures you would try to take.

Fortunately, not all fish tumors are cancerous, and only a professional can tell the difference via performing specific tests for an accurate diagnosis. The fish will display symptoms similar to other bloating-related disorders.

If the belly is large enough, the fish may experience difficulties swimming, lose its appetite, display increased aggression or lethargy, and showcase unusual hiding behavior. Once you’ve identified the tumor, you can consider some treatment procedures, depending on its location, type, and severity.

How to Treat Fish Tumors?

The treatment will vary in effectiveness and type, depending mostly on the tumor’s location, size, and specifics.

Some tumors are rooted deep within the fish’s tissue with multiple capillaries and other blood vessels, making them difficult to remove.

There are mostly 2 potential treatments for tumors:

  1. Cryotherapy – The use of liquid nitrogen designed to destroy the tumor’s cells by forming ice crystals within the tumor’s tissues. These crystals will cut out the tumor’s blood supply, practically starving the cells. You may require multiple cryotherapy sessions to eliminate the tumor completely. This treatment method is mostly used for external tumors.
  2. Surgical intervention – This procedure is more fitting for internal tumors, especially malignant ones. The specialist will sedate the fish and eliminate the cancerous cells rather quickly. The procedure won’t last more than 30 to 60 minutes, depending on the situation.

That being said, you should know that not all fish tumors are operable. Some are too aggressive, growing on vital organs, making it impossible to remove them safely.

It’s also worth noting that internal tumors aren’t visible until reaching later stages. At this point, the recovery may be unlikely. So, don’t get your hopes high.

How to Prevent Bloated Belly in Flowerhorn?

The prevention system should revolve around several defining factors.

These include:

  • Ensure optimal water conditions – Flowerhorns are rather sensitive to an improper water condition, as any respectable cichlid should be. Clean their tank regularly, perform weekly water changes, and remove fish residues and fish waste frequently to prevent ammonia buildup.
  • Avoid overfeeding – Flowerhorns are big cichlids with a fitting appetite. This means it’s rather easy to overfeed them, which could cause constipation, to mention the mildest repercussion. Overfeeding will also affect the water quality, promoting algae overgrowth and supporting the development of harmful pathogens in the tank water.
  • Keep the water temperature stable – If the water drops below the flowerhorn’s comfort level, the fish may experience both digestive and immune-related problems. Cold waters will affect the fish’s immune system, leaving it vulnerable to viral infections. The same problem can be responsible for digestive issues like constipation and severe compaction.
  • Monitor your fish’s health constantly – Early treatment is the most effective treatment. Monitor your flowerhorn daily and act as soon as you observe any abnormal behaviors or physical changes. Identifying and addressing your flowerhorn’s problems in time will increase its chances of recovery dramatically.


Remember: flowerhorns are the result of selective breeding, which means they haven’t evolved naturally. It’s normal for their genetic makeup to display deficiencies or weaknesses that may not be present in wild species.

This means that flowerhorns require careful care and a stable maintenance routine to prevent health problems over the years. Your flowerhorn can live up to 10 years when kept in balanced, healthy, and clean habitats.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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