Why is Your Betta Fish Having a Bloated Belly? (Tips & Fixes)

It might be confusing to see your Betta going from healthy and energetic to puffy and unenthusiastic.

In my experience, there may be multiple reasons why your Betta fish is having a bloated belly and appears to be lethargic. There’s no need to panic, however, since a swollen stomach does not always mean the worst for your aquarium pet fish.

A bloated abdomen may sometimes indicate harmless constipation, and not the fatal Dropsy or the annoying Swim Bladder Disorder.

In this article, I will explore the main causes of bloat in Betta fish.

Knowing how fish bodies work can help to prevent severe illness.

Why is your Betta fish having a bloated tummy?

Looking at your Betta’s swollen abdomen might be overwhelming.

Sometimes the condition may be accompanied by difficulties with swimming and breathing.

There are several reasons for a Betta fish to develop a bloated belly:

A Betta fish may develop a bloated belly due to overfeeding with nutrient-dense foods or a lack of fiber in its diet. Substandard water quality, bacterial infections, or internal parasites may also contribute to bloat in fish.

All of these factors may lead to an expansion of the abdomen in fish and a belly that looks extremely swollen.

Severe constipation and conditions such as Swim Bladder Disorder, or Dropsy are all possible complications that may follow.

If a female Betta has a swollen belly, it may also be that she is egg bound.

All of the aforementioned conditions can be cured as long as they are properly and timely diagnosed.

Let me explain each one in detail.

1. Feeding foods that are too nutrient-dense and break down too quickly

Betta with a severely bloated belly

By Philippac

A bloated abdomen in a Betta can often be a result of the fish eating foods that are too nutrient-dense yet disintegrate too quickly when inside the stomach. These types of foods trigger a negative response that slows the emptying of the stomach.

The function of this body reaction is to prevent the intestines of the Betta fish from getting overwhelmed with nutrients.

A prolonged triggering of this response leads to food retention in the belly of the fish and therefore bloating from severe constipation.

In some cases the stomach may become so swollen it would start appearing white on the outside.

When I was initially researching the possible causes of belly bloat in fish, I stumbled upon this one study that suggested the aforementioned scenario as a possible cause.

The study kind of opened my eyes to the type of foods I was giving my Betta.

Can you guess which foods are too nutrient-dense and get digested too quickly?

If you guessed “pellets” then you’re following.

Pellets are basically compressed flakes that are nonetheless fast dissolvers themselves.

Anyway, the pellets always come with super high protein content and are made to be easily digestible.

Betta fish are also genetically prone to bloat (same as Goldfish) and the two effects seem to stack up quickly.

The mechanism that slows the stomach emptying is called enterogastric control.

When it activates the food remains way longer in the fish’s belly.

If you feed the fish with nutrient-dense types of food for a prolonged period of time, the mechanism would lead to decreased water absorption.

It might seem that this should work against bloating, but not in this particular chain of events.

After doing some more research, I found that decreased water absorption will force the gills of the fish to start extracting more salt from the outside environment and pump it back into its body. Consequently, the increased water retention leads to excessive swelling not only in the abdomen but also throughout the whole body cavity, a symptom known as Dropsy.

The scientists in the study suggest that in such cases the fish should be fasted, and its nutrient intake reduced.

In the case of a Betta fish you’ll likely need to cut the pellets or flakes from its diet entirely.

What closely resembles the menu of a Betta in the wild would be bloodworms, daphnia, and, occasionally, Mysis or brine shrimp.

These foods have some necessary insect fiber that helps digestion, and also lack the high-fat content of flakes and pellets.

The latter are also highly processed and the protein source can often be something that’s not found throughout the natural diet of the fish.

I will recommend a feeding schedule that has worked for me and my fish when nothing else has.

To treat bloating caused by nutrient overload in Betta fish try the following:

  1. Day 1: Fast the fish.
  2. Day 2: Fast the fish.
  3. Day 3: Feed the Betta a tiny amount of bloodworms, once.
  4. Day 4: Fasting.
  5. Day 5: Feed the Betta a small amount of Daphnia, once.
  6. Day 6: Fasting.
  7. Day 7: Feed a small amount of Daphnia or Bloodworm, once.

Make sure to only feed the fish an amount that resembles its eye socket in volume. On feeding days, only feed once.

Repeat this regimen until the bloating subsides completely.

To improve the Betta’s chances of success with this treatment you should also maintain pristine water quality, in order to reduce the stress on the fish.

Don’t do large water changes as these are stressful to the fish and may even kill it on occassions. Instead, perform smaller (no more than 10 to 15%), more frequent ones.

Something that could help with further reducing stress in fish is API’s Stress Coat Plus.

You can find that and all of the aforementioned freeze-dried live foods at most larger pet stores online such as Chewy. Here are some links for your convenience:

2. Bacterial kidney infections

A bacterial infection may be the reason behind a lethargic Betta with an extremely bloated belly. Harmful bacteria may damage the kidneys of fish, hindering their ability to regulate bodily fluids. This causes the body of a fish to absorb too much water, which leads to swelling that often starts from the stomach.

I’ve had the chance to observe a lot of sick Betta fish during my years of helping friends with their fish-keeping endeavors.

Speaking from experience, a hidden bacterial infection is the most common reason for a Betta to mysteriously develop a bloated abdomen out of nowhere.

I should also note that, occasionally, a bacterial infection may develop into an abscess.

Just like the cancerous tumor, an abscess can appear anywhere on the body. When it appears on the Betta’s stomach, the abscess makes the fish look bloated on one side.

To identify it properly you should know that an abscess will have a white spot in the middle of the lump. It can also be entirely white and filled with fluid.

Another symptom of this type of infection is your fish swimming with its fins very close to the body.

The abscess can damage the internal organs of the Betta, leading to Swim Bladder disorders.

Anyway, it’s important to remember that bacterial infections in Betta fish are often the result of poor water conditions and stress.

However, these should be taken care of after the infection has been cured.

On that note, any type of bacterial infection in aquarium fish should be treated immediately.

If no action is taken, the whole cycle will repeat, as Betta’s immune system will be compromised and the fish will be more susceptible to future infections and diseases.

To treat a bacterial infection, isolate your Betta fish in a hospital aquarium, and medicate it there by using antibiotics.

Ensure that there are some hiding spots in the tank, as sick fish will need their personal space to rest.

Start performing regular water changes to avoid the build-up of ammonia and use a good antibacterial medication.

My experience has been that amoxicillin is a sound choice for treating bacterial infections that cause bloating in a Betta.

When I’ve treated Betta fish this way the bloat usually subsides a couple of days after the treatment has been initiated.

Just make sure to use 100% pure Amoxicillin trihydrate.

Fish Aid Antibiotics offer that. I’ve chosen the exact 100% Amoxicillin trihydrate products in those links.

Obviously, you should consult with a vet for best practices.

3. A diet poor on fiber

red Betta fish with a swollen belly

By Guanchy

A diet that’s low on fiber can cause severe constipation in Betta fish, which may eventually lead to bloating. The symptoms of constipation bloat in a Betta could include a swollen stomach, that almost appears white, rare or no defecating, and troubles swimming straight.

To treat a constipated Betta you need to sparingly feed it quality food that’s high on fiber followed by fasting the fish for a couple of days.

Daphnia, which is a type of water flea, can be found in fish stores and is known to provide beneficial fiber and a laxative effect for fish. Bloodworms are also an excellent source of fiber for Betta fish with constipation.

Another option here would be a blanched, deshelled pea. Feed the fish with 1/4th of the pea and skip feeding the next day or two.

I prefer feeding Daphnia or Bloodworms to a Betta fish because these foods are a natural source of fiber for it, whereas the fiber in peas comes from a land-based plant.

Constipation is easily treated in fish and if that’s the reason behind the swollen belly of your Betta, you should see the bloat go away in a couple of days.

Note that you can fast the fish for 2 to 3 days without worrying, because a healthy specimen can live for up to 2 weeks without food.

There are many brands of fiber-rich foods and you can likely use any of them to feed your Betta.

However, if I were to recommend one, I’d suggest going for Omega One’s freeze-dried Bloodworms or this inexpensive 3-in-1 treat from Zoo Med.

Either would do.

4. Internal parasites

A Betta so bloated, it appears its abdomen is white

By Moresia

Sometimes, the belly of a Betta fish can become bloated due to internal parasites.

The most common internal parasites that may cause this are roundworms such as the Camallanus worm. Note that these are not the same as the tiny white worms that may sometimes plague your aquarium if maintenance was lacking.

Anyway, if no treatment is initiated, internal parasites can affect the swim bladder of your Betta and even promote Dropsy. The first is characterized by buoyancy issues and upside-down-swimming and the latter by fluids building up in the whole body of the fish, and not just the stomach.

Other symptoms to confirm a parasitic infection in Betta fish may be:

  • pale body colors
  • white stringy poop;
  • listlessness and lethargy;
  • erratic movements;
  • lack of appetite;
  • eating normally yet losing weight.

It could be surprising to some people that when the Camallanus worms are fully grown, they may be seen coming out of the Betta’s tail area.

This can be a shocking view to someone, as I remember it was for me.

Anyway, you should also check for any redness in that area, and monitor the fish for erratic swimming.

It’s important to remember that some internal parasites will develop over the course of 1 to 6 months.

For this reason, most of them will go unnoticed for long periods of time.

Once you are sure that the bloating of your Betta’s belly is caused by roundworm parasites, you need to treat the whole fish tank and not just the infected fish.

Though the parasites may seem to affect one fish only, the infestation will likely encompass the whole aquarium.

I recommend vacuuming the entire substrate of the aquarium to get rid of any parasitic larvae.

Anyway, in my experience, you can treat the condition with Levamisole, which is actually a medicine for internal parasites in cattle.

I’ve seen it work excellently against parasitic bloat in aquarium fish.

On the other hand, you can get another commercial medicine if you can’t or don’t want to try Levamisole.

Praziquantel is the active ingredient you should be after.

A good product that contains Praziquantel and has proven its worth over time in the fish keeping hobby is Hikari’s PraziPro .

If your Betta fish’s abdomen has become bloated due to internal parasites you should see the swelling subside towards the end of the treatment.

5. Egg Binding

If you notice a swollen abdomen in a female Betta fish and she is over 4 months old, it may be that she’s developing eggs.

If you are not sure whether her belly’s gotten big because of eggs, take a closer look and you should notice a white spot on her tummy.

Also, pay attention if she has vertical stripes suddenly forming on her body.

These are breeding stripes, a good indication that the fish may be carrying eggs.

In the case of egg binding, there’s nothing to worry about.

If you have a male Betta fish, you can place the couple in one tank with a divider, or you can just show the male to the female from a separate fish tank.

This will speed up the process of egg dropping and reduce the bloating of the abdomen in the fish.

6. Overfeeding with large amounts of food

A pale Betta fish with an extremely bloated stomach

By kscarlett20

An overlooked reason for a Betta fish to develop an abnormally swollen stomach is overfeeding.

I remember that in my diligence to make my pet fish happy, I used to overfeed them heavily.

In my defense, I must admit that they always seemed hungry to me.

However, with time I learned that this is a common misconception.

Betta fish are opportunistic feeders in the wild and will consume as much food as they can when given the chance.

For this reason, you should not be surprised if yours looks constantly hungry.

Overfeeding on rare occasions is likely harmless to your Betta fish.

However, continuous overfeeding with dense, nutrient-rich foods such as pellets may lead to constipation, a bloated abdomen, and obesity with fat surrounding the Betta’s internal organs.

Needless to say, adding too much food to the aquarium may also overwhelm its biofilter with organic waste.

If no measures are taken, your Betta fish may end up with a belly that’s so swollen to the point that it appears white. Most importantly, your swimming buddy’s immune system would be compromised.

To avoid overfeeding, you’ll need to feed your fish no more than two times a day – in the morning and in the evening.

I personally prefer to feed my Betta only once a day.

Also, you can fast a Betta for a full day, once a week.

A Betta’s stomach is almost as big as its eye and the common agreement between hobbyists is that these fish don’t need more food volume than that.

Here’s a good regimen that will reduce the chance of a Betta developing a swollen stomach due to overfeeding:

  1. Switch to live or frozen live food instead of compressed, processed pellets or flakes.
  2. Only feed your Betta once a day.
  3. The volume of each meal should resemble the volume of the Betta’s eye.
  4. Skip a feeding day once a week.

7. Temperature Shock

A temperature shock could indirectly cause belly bloat in aquarium fish.

If the temperature becomes too low it can cause the Betta’s metabolism to slow down too much for its digestive system to work properly.

This might lead to a bloated look and internal organ damage.

To avoid this, simply raise the temperature of the aquarium water, by using a heater.

A water temperature of between 79 and 81 °F (26.1 to 27.2 °C) is ideal for most species of Betta fish.

I would like to point out that having a reliable aquarium heater in your small tank really helps.

The link will help you outline the better ones of the smallest heaters as some models can be outright garbage.

Anyway, the bloating of the stomach should subside a couple of days after the water temperature has been brought back to normal.

You will likely see your Betta return to its usual activities in no time.

8. A growing tumor

In some rare cases, the stomach of a Betta fish may become bloated due to a growing tumor.

Tumors may be a result of the fish’s genetics, poor nutrition, or bad water quality in the aquarium.

The symptoms of a tumor may include a lump on one side of the Betta’s belly.

If the bloating is asymmetrical there’s a good chance that your Betta fish may be developing an internal tumor.

However, if the bloating appeared in the past couple of days, it is highly unlikely that it’s caused by a tumor, since tumors take more time to develop.

The best way to confirm or rule out tumor growth in a Betta is by taking the fish to a vet.

Tumors can be both internal and external. When they are internal, there isn’t any real way to detect them by just looking at your Betta.

In both cases, they can press against the organs of a Betta and cause further health issues, such as troubled swimming, difficult breathing, and swim bladder disease.

Additional symptoms might be a lethargic mood and a lack of appetite.

A tumor is really not curable, so what I can recommend here is providing your Betta fish with a comfortable life.

Keep the fish in a well-maintained aquarium, feed it with delicious, preferably live, food.

It should be noted that there are plenty of cases where the fish lives with a tumor for up to three years. This is because tumors do not affect a Betta’s ability to eat, swim, or breathe.

However, if you see any signs of your betta suffering, you should, perhaps, consider euthanasia as an option.

9. Not enough exercise

On rare occasions, the lack of enough swimming might cause bloating through constipation in Betta fish.

A Betta needs space to properly exercise its fins and whole body muscles. Be sure that your Betta has a big enough fish tank to explore, regardless of whether it lives alone or with tank mates.

Some people prefer 2.5 gallons tanks, others say every size smaller than 5 gallons is not big enough for the Betta fish.

My personal opinion is that a 5-gallon tank is the minimum aquarium size for Betta fish. Many experienced fish keepers would agree with me here.

If you think your Siamese fighter lacks enough movement, you can occasionally put a mirror in front of it. When the fish sees its reflection, it will start flaring its gills at it, which is a form of exercise.

You can do this for 1 to 2 minutes every other day.

Don’t go over the suggested time period, and do not leave the mirror in front of the tank.

As with all things the dose makes the poison.

Too much flaring is stressful for Betta fish and can actually weaken their immune system.

10. Malawi Bloat Disease

In rare cases, the stomach of a Betta fish could become swollen due to a disease known as Malawi Bloat.

Though research has been done, the origins of the Malawi Bloat are still unknown.

If the condition is not treated, it will advance and apart from the swollen belly, you will see your fish having trouble with getting enough air.

Your Betta will spend more and more time on the surface of the tank, gasping to get some oxygen.

Also, the fish may get lethargic and lose interest in food.

Its poop will become white and stringy (which is a good sign that Malawi Bloat is the result of an internal parasite).

Before you conclude that your Betta has Malawi bloat, make sure to rule out bacterial and roundworm infections.

The bad news is that if your fish has Malawi bloat, it will likely not end well.

Usually, once it’s diagnosed, it’s already too advanced for anything to be done, but some users report success with Mardel’s Clout.

Clout is one very strong medicine and should be administered with great caution as overdoses can be lethal to aquarium fish.

Malawi Bloat can likely be prevented by keeping the fish tank’s water clean and providing an excellent diet for your Betta.

Don’t mistake symptoms for causes

There are some persistent factual mistakes that have been circulating in this hobby for quite some time now.

More often than not the 2 conditions described below will be cited as a “cause” for bloating in Betta fish.

In fact, they are merely symptoms of the actual cause.

1. Swollen Swim Bladder

The swim bladder is a gas-filled organ that regulates buoyancy in Betta fish. If for some reason, it becomes swollen, it starts pressing against the stomach of the fish, which manifests as a bloated belly.

A swollen swim bladder in Betta fish can be the result of multiple underlying conditions such as:

  • high nitrate in the aquarium water with anything over 20 ppm of NO3 for continuous periods of time;
  • a bacterial infection that causes the swim bladder to collect fluid and expand;
  • gulping excessive air during eating non-sinking fish food, also known as air bloat.

Each underlying condition and its symptoms might affect the swim bladder of Betta fish, and therefore their buoyancy.

If your Betta has a swim bladder disorder, you will see that it’s not swimming but rather floating upside-down at the aquarium’s surface.

It might also sink to the bottom or swim on one side.

At this point, apart from the bloated abdomen, a Betta fish will often refuse to eat.

In some cases where the swim bladder is swollen because of poor water quality, the spine of the fish could become curved.

Before I continue, I think it’s important to make something clear.

Swim Bladder Disorder is more of a consequence rather than a cause for belly bloat in fish. An enlarged swim bladder may cause bloating in Betta fish, yet a swollen belly can become the reason for Swim Bladder Disorder.

Now, you need to find the reason behind swim bladder issues and treat them accordingly.

If it is constipation due to overfeeding with low-fiber foods, you need to fast your fish for a couple of days and introduce fibers from insect exoskeletons in its diet.

You can also move the Betta to a hospital fish tank or give it therapeutic baths with Epsom salt. Those will relieve the swelling of the belly.

If you go for Epsom Salt follow the instructions on the package precisely.

Do not add more salt than 1 tablespoon per 1 gallon of aquarium water.

For parasites, follow the instructions above and use the right medications or simply consult with a fish vet.

Don’t forget to assess the water parameters of the aquarium and make changes if needed.

Liquid-based test kits such as API’s Freshwater Master Test Kit are superior to strips. Stips will be off and do not give a precise measurement of the water’s parameters.

Precision is what you’d want if you’d like to rule out a possible (nitrate) poisoning from poor water quality.

2. Impaired fluid retention – Dropsy

Betta fish severly swollen from Dropsy

By xfriendsonfirex

If left untreated, bacterial infections or internal parasites may result in abnormal fluid retention in Betta fish.

This condition is also known as Dropsy and in its early stages, the fish starts to hold fluids in its abdominal area, which then expands.

This results in an extremely bloated belly for the Betta fish.

To identify Dropsy in Betta fish, check for the following symptoms:

  • bloat in the abdominal area which later spreads to the whole body;
  • sticking scales that give a pinecone outer texture to the Betta fish’s body;
  • lack of appetite;
  • pale coloration;
  • curved spine (rarely);
  • difficulties with swimming;
  • rapid breathing and gasping for air.

Now, I must make clear that, same as the swim bladder disorder, Dropsy (or edema) is a symptom, rather than a disease.

Sick and stressed fish often end up with Dropsy as a final stage of some untreated disease.

Dropsy is often labeled as incurable. However, if it is caught in an early stage, successful treatment with Epsom salt and antibiotics may be possible.

Epsom salt will alleviate the swelling and the antibiotics will take care of the infection itself.

A Betta fish developing Dropsy indicates damaged kidneys or liver, and sometimes both.

Kidneys are responsible for passing water through the urinary tract in fish.

When they are malfunctioning, however, the fish starts retaining a large volume of fluids and the body swells, usually starting with a big abdomen.

When I was first doing research on fluid retention in fish, I found that more often than not the condition is caused by some type of “gram-positive” bacteria in the kidneys.

Gram-positive is a classification of bacteria species based on their cell walls.

For this reason, I usually treat the condition with an antibiotic that targets gram-positive bacteria specifically.

Apparently, some good antibiotics for the purpose would be erythromycin and amoxicillin, as described in this summary by the University of Florida.

Erythromycin can be found in a product known as Mardel Maracyn.

However, I’ve found that amoxicillin works better in this case and generally has a higher chance of success than erythromycin.

You can find amoxicillin at Chewy or any other large online store for pet supplies.

Now onto the treatment itself.

You will need 1 hospital tank where you’ll treat with antibiotics and one tank where you’ll carry out the Epsom salt baths.

Though amoxicillin won’t harm the Gram-Negative nitrifying bacteria in your main aquarium it may disturb the overall ecological balance established by other Gram-Positive bacteria.

Anyway, make sure the water in both tanks shares similar parameters to avoid shocking the Betta fish in between relocations.

Follow the instructions on the packages of both the antibiotic and the Epsom salts.

For the salt baths, use 1 tablespoon of Epsom for each gallon of water and let the fish swim in the mixture for about 20 to 30 minutes.

Know that though Epsom salt may be relieving for the fish, there isn’t any guarantee that it will reduce the bloating.

The real effect will come from the medicine and you should observe the swelling go away in a couple of days.

Ways to prevent a bloated belly in a Betta

The best possible way to prevent your Betta fish from becoming bloated is to take proper care of it and the fish tank from day one.

Feeding your pet fish with high-quality food is essential.

Reduce pellets and flakes to a minimum and interchange them with live, or freeze-dried live food.

You should also fast your fish at least once a week.

Perform regular water change to maintain a quality aquarium environment.

Don’t forget to check the ammonia and nitrate levels, as spikes in those can rapidly induce stress in the fish.

Stress, on the other hand, can and will increase the chances of disease.

You can either do frequent water chemistry tests with a liquid-based test kit or set up an Ammonia Alert indicator that will constantly track NH3 levels in the aquarium.

Avoid placing sharp objects into the tank, as sometimes this can lead to injuries, more stress, and further health issues.

The same goes for the tank mates – Betta fish are aggressive by nature and need some personal space.

For this reason, it is very important to choose the fish they share the aquarium with carefully.

Anyway, give your Betta enough space to swim around and to exercise its body muscles.

Although lots of people choose 2 or 2.5-gallon aquariums for their Betta pets, this is not really enough space for a happy life.

My piece of advice here would be to keep a Betta in a tank that holds no less than 5 gallons of water.

Final Words

Bloating in Betta fish is not an uncommon sight.

While a swollen belly may look scary, in most cases it’s relatively harmless.

However, if the harmless conditions are ruled out, an adequate treatment for an underlying bacterial infection may be your best bet.

Leave me a comment below if you’d like to receive more answers.

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27 thoughts on “Why is Your Betta Fish Having a Bloated Belly? (Tips & Fixes)”

  1. My Betta gets what i consider to be bloated, but then lays a large round poop and the bloat immediately goes away. i’ve ordered some bloodworms, but previously have fasted him and then given a small cut of a pea to help him poop. He goes through this cycle often. I never see him do a regular sized poop. it’s always like he’s giving childbirth, it is truly terrible to watch. Any advice? I don’t believe he is being overfed, I’m about to change up his diet, but anything else to watch out for?

    • Hi Cana,

      Your Betta is passing the food which is good news. It does sound like he’s slightly constipated. Daphnia is the best for introducing fiber to a Betta’s diet. I’d recommend not giving him pea because Betta fish are carnivorous.

      Hope this helps!


  2. My Betta fish suddenly bloated after after I accidentally fed him way too many Betta bug meal pellets. Do you think I should cut out the bug bites completely, or just fast him for a few days and then try a very tiny amount of them again? I just bought an entire container of them and started feeding him them yesterday. I previously fed him tropical flakes, and he did seemed to be fine with those. Thanks!

    • Hi Nataly,

      What brand did you buy?

      If the bloating came from the pellets, I’d say fast your Betta for a few days and then be mindful when feeding.


      • I bought Fluval bug bites, and thank you for your advice!

        • Good choice! 🙂

          Thanks for being a reader

  3. Hi Momchil my Betta has a white bloated belly very even on all sides. She is swimming great, fins open just as normal and has a good appetite. I have only been feeding her Aqueon Betta food and Fluval Bug bites for 8 months.
    She shared a 5 gallon tank with some ghost shrimp and a snail. She enjoyed the company of the shrimp for a couple of months but I believe she has eaten 3 of them as there is only one left.
    We are on day 8 of your fasting regimen but do not see any improvement although the last shrimp disappeared 6 days ago. Anything else I can do? I have pictures and videos but no idea how to post here 🙁

    • Hi,

      If there’s no improvement then you could stop fasting the fish, but keep offering bugs.

      You could try Epsom salt baths combined with an antibiotic (check my discussion with Gretchen in the comments).

      Good luck and don’t lose hope!

  4. Thank you for your website, especially the pictures! My Betta Neon has had a bloated belly for about 2 weeks. I’m fairly sure it is from overfeeding pellets (me feeding + my daughter feeding = too much food!). When we first noticed it, we reduced his feeding to 1 pellet per day. The bloat has gotten larger in the past few days.

    I will start right away with the feeding regimen you describe – we have Blood Worms to give him between fasting days.

    My question is in your response to Barb about starting the “kidney failure” regimen alongside the feeding changes. Neon’s bloat also seemed to appear fairly overnight. Is the kidney failure regimen the amoxicillin you describe? If so, can you buy that at a regular pet/aquarium store? Is it okay to wait on that and see how he does with the fasting/Blood Worms – we are about an hour to a store of that type.

    Thank you!

    • Hi, and sorry for the late reply!

      I’m not sure if any regular pet store would have the stuff. It is a fairly niche product.

      I personally would not wait long if I suspect bacterial infections. How is your Betta doing after switching to the new feeding regimen?


      • We are on day 3 of the new regimen, with no visible change.

        He has fasted now for 2 days, and today is the start of a small bit of Bloodworm. He has not had any change in the size of his bloated belly. He has good energy, swims around a lot – has to swim to keep from sinking. So he divides his time between swimming a bunch and nestling into his hanging shell or leaf hammock to hold him up – he doesn’t tend to like being on the bottom.

        I’m a little unclear about when to suspect a bacterial infection. He doesn’t have the pinecone scales. He swims with his fins sticking straight out, so not at his sides like you describe above. Seems to have his normal level of activity. He had a great appetite this morning with his Bloodworm!

        We live really rural, so would probably need to order the amoxicillin online – would rather order now and have it on hand if needed, if it’s not too expensive. Do you have a brand or store you recommend, and dosage? I see on Chewy.com 250mg and 500mg doses of Fish Aid Antibiotics (100% Amoxicillin). We have a smaller tank, so I’m thinking the lower dose?

        Thanks for your input!!!

        • Hi,

          If he’s not lethargic yet, then it may be safe to wait to see if the feeding regimen works. I’d wait about 10 days and would look for definitive improvements (reduced belly size while still swimming actively, etc.).

          Anyhow, the one I linked to on Chewy would be the one I’d recommend. The smaller bottle should be enough.

          • Thanks for the reply. I went ahead and bought the Fish Aid Antibiotics 250mg from Chewy (100% Amox Trihydrate), to have on hand. I didn’t see your link, so hopefully the bottle I chose will do! I will keep a close eye on him and start the Abx regime when they get here. He does seem to be less active today.

            For administering the Abx, you describe moving the fish to a smaller “hospital” tank – if he is the only one in a small tank, can I just leave him in there? I can take out some of the adornments (moss ball, shells), leaving his favorites for comfort. Moving tanks I would worry about added stress and the stress of too much water change.

            Thanks for the input!

          • Some antibiotics (not all but most of them) will likely stall the Nitrogen cycle in the tank. They may kill the beneficial bacteria responsible for converting ammonia to Nitrate. You’ll need to be very diligent with water changes to avoid the buildup of ammonia. After the treatment is over you should use some sort of beneficial bacteria starter to cycle the tank with the fish inside. On the other hand, I agree about added stress – it’s a valid point. If you’re okay with the consequences it would be better to treat your Betta in its current tank for his own peace.

          • Okay, I will keep him in his own tank and stay up on partial water changes. The instructions said every day between treatments.

            Can I use some water from the other tanks to re-innoculate his tank? We have 2 other Betta tanks. (BTW, they are getting the fast/Bloodworm regimen too as a preventative. Everyone is moving to our new “Wild Betta” diet!)

          • Well, there’s no need for transferring water between tanks. If it is indeed a bacterial infection it could have happened from anything, including water temperature fluctuations and whatnot.

            As for the “wild diet” (hehe), this is, I think, the best thing someone could do for their Betta fish. The fish will be healthier, more resilient, and happier. Well done!

            Now let’s hope everything turns out fine with your bloated guy!

          • Well …… Neon went through the fasting diet you describe above for 1 week, he has been on Amoxicillin for 7 days, and he does not seem to be improving. His bloat is a little bigger, and he has a hard time swimming, because he immediately sinks to the bottom. I am now feeding him a small amount of Blood worm 1 x day and he really cruises to the top of the tank for that!

            Under constipation, you say to repeat the fasting regimen until bloating subsides, so maybe I should do that again. On the other hand, if he is nearly his end, I don’t want to deprive him of his joy in eating. Re-reading everything, I can rule out abscess, internal parasite, egg binding, tumor, malawi bloat, and swim bladder.

            I fear we are moving into Dropsy. I am wondering if I should add in the Epsom Salt Bath as an additional treatment???? I see your instructions for it, to let him swim in the bath for 20-30 minutes. Do I do this once a day, twice a day?

            I will continue with the ABx – the bottle says 10 days, is there any value in continuing beyond that?

            Any other recommendations?

          • Hi, Gretchen

            I’m sorry to hear that. The Dropsy stage rarely improves… Truth is that Dropsy is still not well understood which leads to poor treatment success. I went above and beyond to find the reasons behind it (and did find some plausible ones) and tried to outline them as detailed as possible in this article. If I had to brainstorm for one more possible reason for mysterious Dropsy, I’d say that it’s the hard water that we keep our Betta fish in. See, Betta fish come from soft water in nature, and living in hard and soft water requires different fluid-retention “strategies” in the body of the fish. Anyway, from here on, you could take the fish to a vet and see if they can help with a solution.

            For your other questions – yes the Epsom salt baths should be done once a day. I’d say to try them, nothing to lose.

            Also, I don’t think there’s any value in continuing the Amoxicillin cycle after the recommended period. There should have been some improvement by now. I hope you did remove any carbon in the filter, correct? I’m not entirely sure but I think that it can interfere with the potency of the medicine.

            Along those lines, you can stop fasting your buddy, but IMO do keep offering daphnia/brine shrimp instead of commercial betta foods.

            Good luck!!!

  5. Hi , my name is Ashley and my beta fish was swollen last night . It appeared to come out of no where . My fish doesn’t have any other fish near it . I don’t know what the cause would be . It seems to appear this morning that the swelling went down but the fish still lays to the side and continues to swim regular but then lays again on its side . I fed it two pellets today to see what happens . I don’t know what to do 🙁

    • Hi Ashley,

      If it happened overnight, it may be constipation. Can you get your hands on Daphnia or Brine shrimp? Daphnia has more fiber but Brine shrimp is also good. Feed your Betta fish this for a week and skip feeding once every 3 or 4 days.

      Obviously, it’s best to take the fish to the vet.

      Good luck!

  6. Hi I don’t know what to do about my Male Siamese Fighting Fish Tundra. Around the time I noticed he was bloated, I remember opening a container thinking it was bloodworms and I ended up shaking a lot of pellets into the tank. I think Tundra ate them all. That was maybe a month ago.

    I also have a snail in the tank. Around the time I fed too many pellets, I thought I would get a Mexican lobster to hang out. The Lobster attacked Tundra and he became upset. I moved the lobster. I then got some red finned tetras. Tundra then hid in his floaty log all night and he looked depressed so I moved them all to my secondary tank. He doesnt mind the snail and its funny because he used to lay on top of the sanil. I dont know why.

    He has been bloated not for maybe several weeks and I don’t know how to diagnose him. If I sent a picture, would you be able to guide me so I can make an informed decision on what to do? I’m worried he is too sick to be cured.

    Tundra is in a 10 gallon tank I got just for him. He even has a floaty log, a castle to sleep in and a bridge he likes to hang out in during the day.

    I thought I was a good fish keeper and I sluffed off the bloating at first thinking it will just pass, until I researched. Now I don’t know what to do.

    Currently, for around at least 2 or 3 weeks I feed him peas and I found a place with the water flea daphnia. I change the water more regularly and I use aquarium salt to ease him. I saw a schedule of feed and fast so I will try that.

    I hope he isn’t suffering. He lays on his side more often now, and his belly is bulged seen on both sides.

    Any help or guidance you may offer me would be appreciated. If I had more money I would take Tundra to the vet. He means a lot to me.

    I have had Tundra since mid summer last year.

    Thank You,


    • Hi Mark,

      I’d recommend immediately switching to the feeding regimen I describe in the article and exclude any pellets from Tundra’s diet. Also, Daphnia should be your preferred choice of fiber-rich food for your Betta instead of a pea (Betta fish are carnivores and their digestive system is suited to process meat). From what you describe I think the most likely reason for the bloating is the processed pellet foods. I have a guide on what Betta fish eat in the wild, which you could skim through that will give you more info on the subject.

      Tundra likely isn’t suffering so far, but he may soon. The vet is always the best option for proper diagnosis.

      Good luck to you and Tundra, I think you guys can make it.

      • Thank you Momchil for your article, site and response to my question. I have been feeding Tundra an eyeball of peas. Well, I make sure he eats an eyeball size. Sadly, he is not as agile before his bloat. I couldnt understand the pineconing on a belly, and I hope Im wrong. When I look at his belly I can see a scale that might look like a pinecone. Im quite certain his problem is from overfeeding.

        If there is a possible plausable secondary problem which I cannot detect, what could it be? and also his colors are blue and white when I got him.

        If the diet/over feeding led or is leading to dropsy, or he already has that, would it be mean to keep him alive? I believe he moves the floaty log to watch television. Also, he seems like a very proud fish, and he will not lay down, he is looking up. He looks more comfortable when he rests on his castle.

        Tundra has the power to swim. I believe he gets tired out. He swims to the surface for air. I have an air stone and I will check the water with a test tomorrow. I maintain the tank. I am also still learning. I have has Tundra since last summer.


        • Hi, again Mark,

          Thanks for being a reader!

          Is it not possible to feed Tundra meat (Daphnia or bloodworm) instead of peas? His digestive system needs what it is designed for right now.

          I don’t think it’s mean to keep him alive, as there is still hope, in my opinion. You just need to make sure he eats insects like the aforementioned and not fish flakes, pellets, or vegetables. Ideally, you’d want your Betta fish to stick to these types of food after it gets better. You could order them online if they are not available near your location.

          Anyway, I made sure to describe any possible underlying problems that could make a Betta bloated in the article. It is as far as I can help online.

          Hope this helps!

          • I do have frozen Daphnia which I picked up last week. I get your point now about food thank you!

  7. Great website with lots of helpful info. My Betta Fish Fred became very bloated almost overnight. I inherited him from a school that shutdown for the pandemic and had 0 experience with fish. That’s TMI but I probably overfed him over time. Problem now is he has fasted for 4 full days (had a small bite of shelled pea yesterday) and he still appears as bloated as he did on Day 1. 🙁 He still swims and comes to the surface like he’s hungry and rests a lot on the Betta leaves attached to the tank. I don’t know which treatment to pursue first. Thank you for sharing your research and experience with us!

    • Hi Barb,

      Thanks for reaching out!

      Usually, I’d recommend to first try out the feeding regimen I describe under the “foods that are too nutrient-dense” subheading. However, you mention that your Betta, Fred, has become bloated overnight. To me, this means it could also be a partial failure to regulate body fluids.

      If you’ve been feeding him commercial pellets and overdid it, it’s probably a good idea to switch to fiber-rich meaty foods such as Daphnia and bloodworm and exclude the pellets from the Betta’s diet entirely.

      I would also do the treatment I describe under the “kidney failure” section as it may very well be that.

      It’s really best to combine both treatments if possible. You’ll eliminate either reason without worrying about losing precious time. Bloating in Betta fish doesn’t end well if left untreated…

      Good luck to you and Fred! Ask away questions if you need more answers, and be prepared for whatever end.

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