Bloated Betta

Bloated Betta: Guide to Identifying and Treating Bloat

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One of the most common health problems in betta fish is bloat. But what causes a bloated betta, and will the condition kill your fish?

Keep reading to learn the most likely causes of bloat in betta fish, and find out what you can do to treat the problem and prevent it from happening again.

Key Takeaways

  • Betta Fish Bloat Causes: Bloat in betta fish can stem from several factors, with constipation being the most common, followed by conditions like swim bladder issues, dropsy, Malawi bloat, and occasionally, tumors.
  • Treatments and Prevention: Most bloat cases can be treated with dietary adjustments; however, dropsy and Malawi bloat are more severe. Prevention focuses on clean water, correct temperature, quality diet, and suitable tank conditions.
  • Key to a Healthy Betta: Act promptly when signs of bloat appear and take preventive measures to minimize the risk, which include maintaining water quality, providing a balanced diet, keeping your betta in a large enough tank, and ensuring a safe habitat.

What Is Bloat in Betta Fish?

A bloated betta will appear to have a swollen, protruding belly. Bloat can affect one or both sides of the fish, sometimes causing it to appear lopsided.

A fish with bloat might have trouble swimming and could become trapped at the water’s surface or on the bottom of the tank. That’s extremely dangerous for betta fish because they need to surface frequently to breathe air through their labyrinth organ.

Summary Table

ConstipationSwollen belly, reduced appetite, less waste productionFasting, feeding live/frozen food, peasHigh-quality diet, regular fasting days, avoiding overfeeding
Poor DietSwollen bellySwitch to high-quality betta pellets, including freeze-dried/live foodVaried and balanced diet, avoid flake food
Lack of ExerciseLethargy, difficulty in swimmingEncourage activity with tank size and decorationsAdequate tank size, engaging environment
Swim Bladder DiseaseSwimming difficulty, buoyancy problems, curved backFasting, swim bladder treatments, adjusting dietAvoid overfeeding, maintain water quality
InjurySwollen belly, signs of physical damageConfinement, water quality maintenance, and possibly medications if infection is presentSafe tank environment without sharp objects, secure lid
InfectionSwollen belly, pale/stringy feces, lethargyAntibacterial or antibiotic medication improves water conditionsQuarantine new additions, maintain clean water
ShockSudden changes in swimming behavior, stress signsStabilize water temperature and conditions, minimize stress factorsConsistent tank conditions, gradual acclimation to changes
Internal TumorsSwelling, possible visible growthsOften untreatable, euthanasia may be the most humane option if suffering is significantNot preventable, as tumors can occur randomly
Pregnancy (in females)Swollen belly, presence of eggs, white horizontal stripesNo treatment is necessary for pregnancy; monitor for healthy egg-layingProviding a proper breeding environment, if intentional
Dropsy“Pinecone” scales, extreme swelling, curved spineOften fatal, treatments include antibacterial or antibiotic medication, methylene blue dip as a last resortPrevent stress, maintain excellent water quality, provide a balanced diet
Malawi BloatSwelling, loss of appetite, gulping air at the surfaceTreatment can involve Epsom salt baths, medications like MetroPlex, and hospitalization if neededPrevent with clean water, careful sourcing of live plants and food

What Causes Bloat in Betta Fish?

Several common conditions cause bloat in betta fish.


The primary cause of bloat in betta fish is constipation.

Constipation is extremely easy to treat and prevent. However, although the condition looks alarming, you need not worry too much about your fishy friend, as it’s highly likely that you’ll be able to cure him pretty easily.


In addition to a bloated belly, the following symptoms are a reliable sign of constipation:

Poor Appetite: Bettas are notoriously greedy fish, so you’ll soon notice if your betta isn’t eating as voraciously as it usually does. A constipated fish will quickly stop eating, and that’s typically the first sign that your betta is constipated.

Less Waste: If your betta is constipated, he won’t be able to pass feces. However, bettas don’t produce a lot of waste, so it can be difficult to tell if your fish is pooping normally!


If you know what makes your fish constipated in the first place, you can take steps to prevent it.

So, what causes constipation?

  • Poor Diet: The main cause of constipation in fish is poor diet. If you feed your fish too much poor-quality food, it can result in constipation, leading to a bloated stomach.Always give your fish the very best quality betta pellets, and include frozen, freeze-dried, and live food in his diet too. Avoid feeding betta fish flake food, as that can very easily cause constipation.

Feed your betta fish only as much as he will eat within a couple of minutes. Also, leave one day per week when you don’t feed your betta at all. That “fasting” day will allow excess food to pass through the fish’s digestive tract rather than becoming blocked up.

I don’t feed my betta if I go away for a couple of days. Now, please don’t throw your hands up in horror and exclaim that I’m a “bad mom” to my pet! In the wild, betta fish don’t always have regular meals, depending on what’s available to them, so they often go for days without eating at all. Fasting is actually very good for your betta, as it allows your pet’s digestive system to process any food before more is added, helping to prevent constipation and bloating.

  • Lack of Exercise: Fish need exercise! Your betta fish needs to keep moving around to help push food through its digestive system. If you keep your betta in a tank that’s too small, he will get bored and frustrated, as well as being at risk of becoming constipated.

Remember, wild male betta fish have a territory of around three square feet, so a tiny bowl or betta vase is simply not a humane environment for your fish!

Your betta should be kept in a tank that’s at least ten gallons in capacity, preferably bigger. You can read all about how to correctly set up a betta habitat in the article at this link.


The treatment of constipation in betta fish is extremely simple. Usually, fasting your betta for two to three days is sufficient to get their bowels moving properly again.

After the fasting period, start feeding your betta live and frozen food, including daphnia, brine shrimp, and mosquito larvae. These foods will introduce more fiber into the fish’s digestive system, which will, in turn, relieve your fishy friend’s constipation.

Always obtain live food from a reputable supplier! Live foods often come with a cargo of unwanted bacteria and parasites that could make your pet sick. For that reason, I prefer to use frozen meaty foods for my fish. They are just as nutritious, risk-free, and easier to store than living food sources.

Swim Bladder Disease

Swim bladder disease is another common cause of bloat in betta fish. However, swim bladder problems can also be caused by constipation and vice versa.

Swim bladder disease is not a disease in the truest sense of the word; it’s simply the common name that’s given to the condition. Swim bladder disease can affect most species of fish, including bettas.


A fish with swim bladder disease will have a bloated belly and will struggle to swim properly. You’ll notice that your fish is having problems with buoyancy, sinking to the bottom of the tank, or being stuck on the surface. Sometimes, fish with swim bladder disease become trapped on one side and can barely swim at all.

Fish with swim bladder disease typically have a reduced appetite, and, in extreme cases, your betta could develop a curved back.


There are several causes of swim bladder disease

  • Constipation: Like bloating, swim bladder disease is often caused by constipation.
  • Injury: Swim bladder problems can also be caused by an injury. Injuries occur as a result of nips from aggressive tank mates or can be caused by your betta fish damaging himself on something sharp or rough in his tank.Your betta might even jump out of his tank and injure himself on landing. So, always put a lid on your betta tank or at least cover it, leaving an inch or so between the water surface and the cover so that your betta can breathe and feed easily.
  • Infection: In rare cases, swim bladder disease in betta fish can be caused by bacterial infection or attack by parasites. In these cases, you may notice that your betta’s feces are very pale and stringy rather than firm and dark brown.
  • Shock: Shock can also cause swim bladder problems. Shock in fish can be caused by rapid temperature changes, fluctuations in the correct water pH, and frequent changes in the lighting in the tank. In cases of shock, fixing the underlying cause usually cures the swim bladder problem too.
  • Treatment

There are several ways of treating swim bladder disease, depending on the cause.

Try fasting your fish for a few days and then offering him live or frozen food. If that treatment is unsuccessful, try using a proprietary swim bladder treatment that you can buy over the counter in most good fish stores.


Dropsy is another cause of bloat in betta fish. Unfortunately, dropsy is very difficult to treat, and there is a good chance that your fish will die or that you will need to euthanize him humanely.


In addition to a bloated appearance, fish with dropsy develop “pinecone” scales. That’s where the scales stand up, giving the fish the appearance of a pinecone. The effect is caused by internal organ damage. The damaged organs swell, causing the fish’s body to bloat and pushing the scales outward.

As the internal swelling increases, the fish’s spine begins to curve outward sideways.


Dropsy has various causes:

  • Stress: Stress in betta fish that often leads to dropsy is often caused by poor water quality, incorrect diet, and other illnesses. Continued exposure to stress weakens the fish and damages his immune system until he can no longer fight off illness.
  • Internal Injury: Internal damage can cause the betta’s internal organs to swell as part of the healing process, giving your fish a bloated appearance. Internal injury can happen during your betta’s move from the fish store to his new home. Bettas can also sustain internal injuries by bumping into objects inside the tank or fighting.
  • Infection: Bacterial diseases can also cause dropsy.


Unfortunately, dropsy is incredibly difficult to treat successfully.

However, you could try to aid your betta’s recovery by carrying out frequent water changes and administering an antibacterial or antibiotic. It may also be worth trying dipping your betta in a methylene blue bath.

Malawi bloat

Malawi bloat is a rare condition that commonly affects cichlids, although it is sometimes seen in betta fish.


Malawi bloat causes the fish to swell. Also, your betta may stop eating. As the condition progresses, the fish will spend a lot of its time at the surface of the water, gulping air.


Malawi bloat is caused by parasites or bacteria in the tank water.

The best way to prevent the condition is by keeping your tank water clean. If you buy live plants or live food, always make sure that the supplier has a good reputation, and never try to source live food from the natural environment, as you could be unwittingly introducing disease into your tank.


Reddit contributor, Darkover_fan, provides a detailed review of how she cured her fish of Malawi bloat in her post, and I thought you might find it helpful, so I included it here:

I thought it might be helpful for others to share how I treated my peacock cichlid for Malawi bloat – or at least, that’s what I think he had. I came home from a weekend away to find him grossly bloated, not yet pineconed, but not eating.

I immediately isolated him in a breeder net inside the main tank (my quarantine tank is full of other fish at the moment). I made a mix of frozen peas (microwaved, skins off, and mashed) with some MetroPlex and a few soaked fish food pellets (just a few), then put the mixture in the freezer in small balls to keep. For the first few days, I treated the whole tank with the MetroPlex in the water and monitored to see if he would poop (he wouldn’t eat), but he only got worse, and he started to pinecone. So, I got some pure Epsom salts online and started the following regime:

3x/day, he got a 30-minute bath in Epsom Salts (5g in 2 lb 2 oz tank water), with a low dose of Epsom salts in the tank (~1g/30 gallons)

I did a second dose of MetroPlex in the tank before I ran out, and then I did 2 doses of MelaFix over the next week.

Since he wouldn’t eat, I had to get him laxatives/nutrition by force-feeding him. I mixed Epsom salts with tank water and mashed the frozen peas/meds mixture in with it, then used a 1 mL syringe (without a needle) to push the mixture down his throat a bit. I did this a total of twice a week and then waited to see if he could/would poop.

This process took all told about 3 weeks – he only got force-fed 3 times over the last 10 days, but he finally pooped, and now it seems all good again! I’m keeping him isolated for a few more days while I get him back on normal food, just in case.


Sometimes, a bloated belly in a betta fish can be caused by an internal tumor.

It’s not possible to prevent tumors from affecting your betta. Just like people, some fish develop cancer, and there’s nothing you can do about that. That said, tumors aren’t very common in bettas, and it’s more likely that your fish’s condition is caused by something else.


If you have a sorority of female betta fish in a tank with a male betta and it’s a female fish that is bloated, it’s possible that condition could be caused by eggs inside the fish.

Other signs to look out for include the appearance of white horizontal stripes running across the fish’s body and the appearance of an obvious white spot on the fish’s abdomen. The white spot is the opening of the ovipositor, a tube through which the eggs are dropped.

Bloated Betta? Take Action Right Away!

Bloated Betta

The best way to give your bloated betta the best chance of recovery is to act quickly; don’t wait for a few days to see if the condition simply disappears!

The first thing to do is to try to diagnose what’s causing your betta to be bloated.

If the problem is simply caused by constipation, then your fish can stay in its main tank.

However, if you’re not convinced that constipation is causing your betta’s bloat, and he lives with a community of other fish, then you should move him to a quarantine tank.

Moving your fish will stress him to some degree, but a temporary relocation will prevent his tankmates from becoming sick. Also, treating your betta will be much easier if he’s living in isolation, and he will find it easier to rest and recover without being hassled by his tankmates.

Once you have moved your betta fish to the quarantine tank, start whatever treatment is appropriate. Keep your betta in quarantine until he has made a full recovery. The stress of moving him back to your display tank could trigger a relapse if your betta hasn’t completely recovered from whatever caused him to bloat.

While your betta is undergoing treatment, observe him for changes in his condition.

Preventing Bloat in Betta Fish

Prevention is better than cure when it comes to bloat, and preventing the condition is pretty straightforward.


Always provide your betta fish with a clean tank. Performing a 25% water change each week will help to remove ammonia and fish waste from the tank. Also, water changes can help to remove harmful parasites and bacteria from the tank.

The lower the levels of ammonia and organic waste products that your tank contains, the lower the levels of nitrites and nitrates will be, which is great news for your fish. You should also have a proper filtration system installed in the tank to process and remove nitrites and nitrates from the water, keeping the environment healthy for your fish.


The water temperature in your betta’s tank should be a constant 780 Fahrenheit. If the temperature falls too low, your betta could suffer from temperature shock, which will expose him to diseases and make it harder for him to digest his food, potentially causing constipation and bloat.

Proper Diet

Make sure that everything you feed to your fish is of the highest quality. Keep your betta’s diet well-balanced by feeding him betta pellets, and remember to include some live food, freeze-dried protein, and frozen food, such as bloodworms, daphnia, mosquito larvae, etc.

Tankmates and Decor

Ensure that the tank environment is safe for your betta fish. Avoid introducing aggressive tankmates, and use only smooth-sided decorations and live plants rather than sharp plastic ones, which could injure your betta.

Tank Size

Keep your betta in a tank that’s at least ten gallons in capacity. Never overcrowd the tank. Too many fish in the habitat places an increased burden on the filtration system and will also stress your betta.

In Summary

Bloat is a common condition that affects betta fish. Fortunately, most of the causes of bloat are easily treatable.

Ensure the tank environment is suitable and safe for your pet, feed your betta a high-quality diet of betta pellets, and be sure to include plenty of live, freeze-dried, and frozen meat protein too. Keep on top of tank maintenance to keep the water quality pristine, and be sure to replace spent filter media when required.

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