Betta Stomach Exploded – 7 Possible Causes & Treatments

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Bettas are the queens of aquariums, and nobody can deny that. They have a gorgeous presence with large and fluffy fins and come in a variety of colors and patterns. Having several Bettas in your tank will bring uniqueness, color, and style to the environment.

All these aspects make it that much more difficult when you lose one or more of your fish. The situation is even worse when your Betta goes off violently by having its stomach bursting.

It’s a gruesome sight that will leave many Betta keepers dumbfounded, especially if they were unaware that that could happen.

Today, we will discuss Bettas and the reason why their stomachs may burst seemingly out of nowhere. We will also see if there’s something you can do to prevent such a grim scenario.

Why Do Betta Fish Stomachs Explode?

There are 7 main causes for your Betta’s stomachs exploding, leading to a gruesome death. These include:

– Bacterial Infections

Your Bettas may contract bacterial infections for a variety of reasons. These include water toxins and chemicals, accumulation of harmful bacteria, and even Bettas’ lower immune system. Feeding your betta fish bread or other forbidden foods can also cause bacteria to bloom in the tank.

Multiple factors will affect your Bettas’ immune system, including stress, disease, poor dieting, injuries, etc. When that happens, the Bettas’ mucoprotein coating will begin to fail. This is a protective coat giving the fish that slippery feel like it’s covered in oil.

This protective coat is a barrier against parasites and bacteria. A lower immune system will cause the Betta to lose its coating, leaving it vulnerable to bacterial infections.

You can tell that your Betta has been affected by noticing its erratic swimming patterns, lower appetite, and constant lethargy. The Betta may also display a white, cloudy slime covering its body in certain areas, along with patches of white skin and sores.

At that point, treatment is necessary to prevent the situation from aggravating, which can spell death for your Betta.

How To Treat Bacterial Infections?

In case of any signs of bacterial infections, I recommend quarantining the sick fish immediately. You can then use potent antibiotics like Tetracycline or Ampicillin in the recommended dosages to counter the infection and destroy the harmful organisms.

These antibiotics are also useful for combating fungal infections. Plus, you should perform water changes every other day to provide the sick Betta with a clean and fresh habitat until the ordeal is over.

If nothing works, euthanasia remains your only option to prevent the infection from spreading to the rest of the population.

– Kidney Failure

Bettas, like any other fish, lack bone marrow. This means that their kidneys are also responsible for producing red and white blood cells, aside from their usual detoxification role.

This makes their kidney work overtime, making them sensitive to a variety of factors. These include infections, diseases, bacteria, parasites, and even stress. Prolonged stress will affect the Bettas’ immune system, causing a variety of health issues, including kidney failure.

When that happens, your fish will display a bloated belly, along with buoyancy problems, lack of appetite, etc. When that happens, you must act fast because these are also signs of Dropsy, which can be deadly.

How To Treat Kidney Failure?

The treatment generally depends on the cause of the disorder. Polycystic Kidney Disease (PKD), for instance, has no cure. On the other hand, Dropsy may be solved with as little as performing water changes and cleansing the aquarium, but not always.

However, the most important thing is to quarantine the sick fish until you figure out what’s going on.

– Dropsy Disease

The Dropsy disease is unjustly called a disease since, in reality, it’s a symptom of another underlying condition. Dropsy refers to the accumulation of fluid inside’s a fish’s body, leading to dangerous inflammation and an inflated belly.

However, there may be multiple conditions causing Dropsy, including bacterial infections, parasites, liver dysfunction, etc. This is precisely what makes Dropsy so dangerous; in some cases, the cause may be benign, while it can be deadly and contagious in others.

How To Treat Dropsy?

First, you must quarantine the sick Betta. This is to ensure that whatever’s causing the Dropsy is not contagious.

The treatment will then vary depending on the nature of the disease. You may need to use antibiotics, parasite-specific medication, and perform regular water changes during the fish’s recovery period. If the disease has no cure or it’s so advanced that the treatment no longer works, you should consider euthanasia.

By no means should you reintroduce the fish to the main tank if you’re not 100% sure that their disorder is behind them.

– Internal Parasite

Your Bettas may struggle with internal and external parasites without you even knowing it. These organisms will generally come into the tank via already infected fish or dirty water.

The internal ones are more difficult to diagnose in the early phases, making them more dangerous than the external ones. Some common symptoms of parasitic infections include swollen belly and eyes, larger periods of inactivity, lack of appetite, rubbing against plants and rocks, etc.

Bettas may also display erratic swimming, lethargy, and lose weight inexplicably as the parasites deprive the fish of essential nutrients. At that point, quarantining the fish is key to protecting the remaining Bettas.

How To Treat Internal Parasites?

While internal parasites are not always contagious, the risk is always there. After isolating the fish, you should perform daily water changes, changing the entire water volume.

You should then use anti-parasite medication to force the organisms to leave the Betta’s system.

A key thing to remember is that internal parasites will keep a low profile. You can’t really tell that your Betta is sick in the beginning, except for its visible weight loss. This can lead you to ignore the issue with fatal consequences for your fish since internal parasitic infections are usually deadly.

Timely treatment is imperative to save your fish’s life and protect the rest of the population.

– Constipation

Bettas can become constipated for a variety of reasons. These include lack of dietary fiber, overfeeding, and even eating dry food too often, like pellets and flakes.

Fortunately, constipation isn’t contagious, but it will turn deadly if left untreated. You should be able to tell that your Betta is constipated simply by looking at it. The fish will display a severely bloated abdomen, along with a total lack of defecation.

At this point, immediate treatment is necessary to help the Betta recover and prevent more serious complications along the way.

How To Treat Fish Constipation?

The treatment is as easy as not feeding the fish for a couple of days. The Betta will be fine, they can go multiple days without food. This break in the fish’s feeding pattern will allow its digestive system to unclog itself.

You can also increase the water’s temperature to around 80 degrees F and feed the Betta boiled and crushed pea. This contains a lot of fibers, aiding indigestion.

You should see your fish overcoming the problem shortly. Either that or its situation will worsen progressively, at which point there’s little you can do.

– Overfeeding

This is a rather confusing topic since overfeeding isn’t a health problem but a feeding behavior. Even more, it’s one where, unlike health problems, you control the situation since you’re the one overfeeding the fish.

Bettas, like all fish, will eat as much and as often as they can. Their brains don’t have a ‘that’s enough’ mechanism, like those of humans,’ because they cannot reason. As a result, your Betta may eat more than it needs to, which may lead to dangerous bloating and constipation.

The situation can grow so severe that the fish’s belly may explode; that’s how greedy they can become. Not to mention, overfeeding comes with several other hazards, including water poisoning.

The unconsumed food will gather in the substrate, decaying and increasing the ammonia levels. This will cause ammonia poisoning, which is deadly for all tank occupants.

How To Treat Overfeeding Problems?

It’s simple – stop overfeeding your Bettas. Like with any condition, prevention is key, along with a balanced diet and schedule. Perfectly balanced, as all things should be, as someone I personally know would say.

Your Bettas shouldn’t eat more than once or twice per day, depending on their size and appetite.

If you notice your Bettas experiencing feeding issues like inflated bellies, lethargy, and erratic swimming, avoid feeding them for a while. One or 2 days should be enough for your Bettas to overcome their problems and allow their digestive system to return to normal.

– Poor Water Conditions

Bettas thrive in clean and fresh water, providing them with stable temperatures, adequate oxygenation, and a refreshing environment. A dirty tank will foul the water, causing a variety of problems along the way.

Some common things that will affect the water’s quality include:

  • Overfeeding – Unconsumed food will foul the tank’s water by decaying and increasing the levels of nitrates and ammonia. These can turn the environment deadly for your Bettas.
  • Fish waste – Allowing fish waste to accumulate in dangerous quantities can also lead to ammonia poisoning. This problem is more typical for overcrowded aquariums that require cleaning more often.
  • Dead fish and plants – It’s often difficult to notice dead fish, especially if we’re talking about Neon Tetras, guppies, and other smaller species living with your Bettas. Their bodies may get lost among the plants, decomposing in the water and spiking the ammonia levels as a result. The same thing happens with dead plants rotting in the water for more extended periods.
  • Algae overgrowth – Unclean tanks will soon cause algae overgrowth, which will lead to poorer oxygen levels and dangerously high bacterial content. These harmful bacteria may infest your fish, causing an array of health conditions along the way.

How To Provide Betta Fish Better Water Conditions?

I recommend changing at least 50% of the water volume every week. This will eliminate or, at least, control the levels of harmful bacteria, improve oxygenation, and stabilize the aquatic system.

A potent filtering system is also necessary to prevent ammonia buildup and keep the TDS (Total Dissolved Solids) to a minimum.

I also recommend always verifying the tank for sick, dying, or dead fish and regularly cleaning the substrate. This will prevent fish waste accumulation and allow you to remove any unconsumed food residues.


As you can see, there are many reasons why your Bettas could die literally overnight. The good news is you almost always have tale-telling signs warning of the impending doom.

One of the most noticeable ones is the inflated belly, which can be a symptom for anything, really. This is why quarantining the problematic fish is always the smartest first step. This will protect the general Betta population from whatever condition the fish might be experiencing.

After you’ve isolated the sick Betta, you can proceed to diagnose its problem and seek for a viable treatment. If nothing works, I highly advise euthanasia as the last safe resort. It’s always better to sacrifice one fish than endanger your entire aquarium life.

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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