Why is Betta Fish Bloated (Swollen Belly)? Causes & Treatment!

If you wake up one morning and find your betta fish bloated (a swollen belly), don’t panic!

There are several reasons for bloating in Betta fish, and most of them are treatable.

You may naturally fear that your fish may not survive. However, the situation is very likely to be in your control.

Here is a rundown of everything you need to know about betta fish bloating and what you can do to make it better:

Symptoms of Bloating in Betta Fish

Bloating is easily noticeable through an outward protruding belly.

It is pretty easy to tell when your Betta is bloated but isolating a cause for it might be tricky.

Since there are several causes for why a betta fish might bloat, each cause has different symptoms too.

You will have to pair the swollen belly and other specific symptoms to determine a singular cause for why your Betta fish has to bloat.

Causes for Bloating in Betta Fish

Some causes for bloating in Betta fish are common, while some are rare.

Whatever the cause may be, the key is to diagnose the correct symptoms and administer treatment to ensure your Betta fish’s health.


Constipation is the most common cause of Betta fish bloating.

Luckily, the prevention and treatment are pretty easy.

If you are better, fish is generally healthy and is suddenly facing some bloating; constipation is probably the most plausible cause.

How can you tell?

If your Betta fish is suffering from constipation, it will also have symptoms such as lack of appetite and inability to pass feces, in addition to a bloated swollen belly.

Lack of Appetite

Betta fish is a species with large guts, which is why it doesn’t take them much time to consume their food.

The only time they do feel full or not hungry is when they are constipated. So if you’re betta fish isn’t eating, but has a swollen belly, it’s probably constipation.

Inability to Defecate

If you keep a close check on your Betta, you may notice how it may not be able to defecate.

If that’s the case, then constipation treatment is what your fish needs.

What’s causing it?

Usually, constipation is a result of dietary problems and inactivity in fish.

Poor Diet

It is unhealthy for you to feed your Betta fish more food than it needs.

In addition, if you are feeding your fish food that may not be the best quality, it can lead to constipation.

Always incorporate live, frozen, or freeze-dried food in your Betta’s diet.

Lack of Exercise

If your Betta fish is in a tank of fewer than 5 gallons, it is probably not getting enough room to exercise.

This can lead to frustration, stress, constipation, and eventually bloating.


You can easily treat constipation in your Betta fish by providing it with a balanced diet. Do not feed it too much or too little.

Balance is necessary not just in terms of quantity but also in terms of quality.

If you feed your Betta with only dry pellets, this can cause constipation more often.

Soft, live food will keep your Betta fish’s bowel movements regular and healthy.

And if you’re keeping your betta in a small tank, better to invest in a bigger one so that your betta has enough space to swim freely and be happier.


Dropsy can cause a fluid buildup within your Betta’s body. This can give the appearance of a bloated belly.

If your fish has dropsy, the chances of it surviving are incredibly slim.

How can you tell?

Other than a bloated belly, you may notice the following:

Curved Spine

As the swelling causes more damage, a Betta’s spine may curve outwards.

Pinecone Scales

A pretty big giveaway is that your Betta’s scales will be sticking out the wrong way.

This happens when the organs are swollen, pushing the scales outward with the bloating.

What’s causing it?

There are a variety of causes for Dropsy, but stress is the most common one.

Several factors can stress a Betta fish out:


If your Betta was already suffering from some sort of disease, there is a higher chance for it to develop dropsy.

Poor Tank Conditions

An unclean tank with poor water quality can also lead to dropsy.

Poor water or food conditions can give your Betta a lot of stress.

Internal Damage

If you’ve moved your fish around a lot, or if it is exposed to any sharp objects, then internal damage is a plausible reason.

Sometimes if your Betta fish has hostile tankmates, they can fight and hurt each other. This is an incredibly stressful situation for a Betta.


The most common treatment for dropsy is to frequently change your tank’s water.

Additionally, you should also treat the water with some antibiotic or methylene blue dips.

With either treatment, chances of survival after dropsy are not very high.

Swim Bladder Disease

If you are sure your Betta doesn’t have constipation, then there is a high chance it has Swim Bladder Disease.

It is crucial to understand that constipation and Swim Bladder disease are sometimes interlinked – meaning that one may cause the other.

How can you tell?

Swim Bladder Disease symptoms are quite easy to spot:

Lack of Appetite

Similar to constipation, if your Betta is suffering from Swim Bladder Disease, it is most likely to reduce or stop food consumption.

Trouble in Swimming

A Betta fish is most likely to struggle while swimming with a bloated belly.

It may stay stuck near the water surface, sink down to the bottom, or even display lopsided swimming.

This particular symptom is a clear sign of Swim Bladder Disease.


If your Betta fish is appearing dull and isn’t moving around anymore, then it is another clear indicator of Swim Bladder Disease.

Curved Back

In extreme swim bladder disease cases, a betta fish may have a curved back.

This is an indication for you to act as quickly as possible because it is an extremely uncomfortable and stressful position for a fish to be in.

What’s causing it?

A big problem regarding Swim Bladder disease is the number of causes it has.

It can become difficult to pinpoint what could actually be causing it.


If your fish is experiencing bloating due to Swim Bladder Disease, then Swim Bladder Disease might be due to constipation.

Swimming difficulty and bloating together are signs of constipation as a cause.


Constantly changing environments with fluctuating temperature, lighting, and pH can be incredibly shocking for your Betta fish.

A consistent and calm environment is most likely to fix the Swim Bladder disease.

Bacteria & Parasites

Bacterial infection is a rare cause of Swim Bladder Disease. However, if it is the case, then you may notice a color change in their stool.

It may appear white instead of brown and stringy in texture.


If your Betta’s tank mates are aggressive or the tank has any sharp objects that can harm your Betta, the injury can cause Swim Bladder disease.


You can treat Swim Bladder Disease in several different ways, with the most common one being taking it out of a stressful situation or a state of shock.

Make sure the environment you are providing your Betta is consistent.

Another treatment could be letting your Betta fish fast if overeating has been an issue.

Other than this, Epsom salts also help relieve constipation in fish.


There is an exceedingly rare chance that a bloated belly is a reason for a tumor in your Betta fish.

Unfortunately, this is something that cannot be treated.

Even though it is extremely rare, a tumor is something you cannot control or treat.

However, tumors in Betta aren’t common, so this shouldn’t really be a huge concern.

Fertile Season

If your female Betta fish appears bloated, then she may be fertile.

She may be producing eggs in her body, which can lead to some form of swelling.

Additional signs of your female Betta producing eggs can be white stripes running across her body.

A white tube may also be visible, indicating where the eggs will be released from.

How Can You Prevent Bloating in Betta Fish?

Follow these steps to prevent further bloating issues in your Betta fish:

Optimal Tank Size

Your Betta fish needs at least 5 gallons or more to move around freely.

Anything less than that can cause inactivity and stress.

Provide High-quality Food

High-quality live, frozen, or freeze-dried fish food should be part of your Betta’s diet.

Only dry pellets are dangerous, and it doesn’t fulfill the nutritional value your Betta fish needs.

Ensure Clean Water

The water in the tank should be changed regularly, but not so frequently that it stresses the Betta.

Remove leftover food and stool as soon as you see it to avoid making the water musty.


It is common for Betta fish to be bloated. In most cases, you can find a suitable treatment and eradicate the cause.

Following proper monitoring and caring steps will always help in terms of accurate diagnosis and treatment for your Betta fish.

Always keep a check on your Betta’s behavior to ensure its optimal health and living environment.

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