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How to Treat Swim Bladder Disease in Aquarium Fish

Swim bladder disease is unfortunately a common issue in pet owners, especially for betta fish and goldfish. A floating fish can be difficult to deal with because there are many causes and a lot of misinformation out there. 

And if left untreated they can prevent fish from eating and even result in death. So how can we deal with swim bladder disease in aquarium fish effectively? 

How to Treat Swim Bladder Disease in Aquarium Fish
found on reddit

Causes of Swim Bladder Disease

The main cause for fish bladder disease is gas misregulation within the swim bladder or fluid buildup displacing some of the internal gas. For aquarium fish this is often a sign of an internal bacterial infection. I discuss a similar disease in this article called Dropsy in Aquarium Fish. However in some diseases the fluid ends up in the swim bladder rather than the internal body cavity, changing how the fish floats.

In fact, any internal organ issue can also impact the swim bladder, causing disease. Parasitic cysts on internal organs, heavy pregnancy in livebearers like Guppies, egg bound female fish, and even fat accumulation (usually in predatory fish fed poultry or meat too often). Any of these can result in a floating fish that is still alive.

Sometimes there can even be a birth defect that causes an issue with the swim bladder but these aren’t at all common. However, goldfish swim bladder disorders are unfortunately very common in fancy breeds. They are so inbred and their internal body structures have become so changed from their wild ancestors that they sometimes can’t properly swim at all.

Goldfish are in double trouble since they are physostomous fish, capable of gulping air to quickly inflate or deflate the swim bladder. Since their internal organs are already misshaped, blockages can happen from infections, another internal organ becoming swollen, or fluid buildup.

Spinal curvature, poor swimming patterns, deformed fins, and other genetic issues can also show up in other fish. If you see these in a fish that hasn’t been bred for these traits, its swim bladder disease is likely genetic.

Other Causes of Fish Bladder Disease

Just because a fish is having trouble with maintaining buoyancy doesn’t mean that the swim bladder is the problem. There are many other reasons why a fish could be struggling to stay in position while swimming.

For example, digestive issues in aquarium fish are very common. More common than actual swim bladder disorder, in fact. Betta fish kept in cold temperatures are very prone to bloating. Like most fish they are ectothermic, meaning their metabolism is regulated by the temperature of their environment.

Betta fish are tropical fish and need a heater but they are tolerant of short periods of cold temperatures. But during these cold periods their digestion and metabolism slows down. As it does so the bacteria in their intestines can start reproducing out of control since food is sitting in the gut longer than it should.

As the bacteria feed they produce excess gas that impacts the buoyancy of the fish. Since floating fish can’t easily release intestinal gas like mammals do it causes them to end up floating if too much gas accumulates. A betta fish swimming upside down more likely is having digestive issues rather than actual swim bladder disease.

Symptoms of a Swim Bladder Disorder

Symptoms of a Swim Bladder Disorder
found on Flickr

For the sake of simplicity, I’m going to include all internal infections that impact the swim bladder in this list, regardless of whether it’s a primary or secondary condition:

  • You see the fish continually floating upwards, which it tries to fight
  • Fish is swimming sideways or in a very wobbly manner
  • Fish sinking to bottom of the tank, often upside down
  • The fish is swimming near the surface continually, often upside down
  • Visible bloating of stomach (scales may or may not be distended)
  • Loss of appetite and interest in moving
  • Labored breathing

Can a Fish Recover from Swim Bladder Disease?

Fish can recover from swim bladder disease but it is not easy. For starters, it can be difficult to impossible to properly diagnose the actual cause of the disorder without the help of a veterinarian who knows fish disease.

Fortunately, many swim bladder issues will fix themselves as the internal infection clears up. Fish may also eventually expel any built up gases, re-inflate their swim bladder, or do whatever else is required for good health.

There are a few things you can do as well, which we will explore below!

How Long Can a Fish Live with Swim Bladder Disease?

It is hard to say how long a fish can live with swim bladder disease since it depends on the cause. If the origin is genetic then the fish will likely be able to live for months to years. But diseases caused by infections can be fatal in just a few days if left untreated.

Swim bladder diseases caused by gas regulation issues aren’t fatal to begin with. But if they don’t resolve themselves soon they will interfere with the fish finding food, which will impact its survival over time. So it’s always better to err on the side of caution and treat any swim bladder disease swiftly!

Let’s now talk about what the swim bladder is and its role in the body of a fish!

What is the Swim Bladder?

What is the Swim Bladder

The swim bladder is an essential organ that serves several functions in aquarium fish. Its most obvious function is to maintain neutral buoyancy relative to the water, keeping fish from either sinking or floating too strongly.

However the position of the swim bladder in the body also helps fish maintain lateral stability so it isn’t tipping along its X-axis while swimming. Some fish can even breathe through their swim bladders! Lungfish are a famous example and proof that the swim bladder is what evolved over time to become lungs in land animals like us!

That said, the swim bladder isn’t found in every single fish. Sharks, rays, and other cartilaginous fish don’t have one at all; they rely on fats and oils or dynamic swimming to maintain buoyancy.

Many fish have the ability to change how much gas is contained in the swim bladder. There are two main designs: physostomous swim bladders, which have a duct leading to the throat or intestines.

And physoclistous swim bladders, which are sealed and rely on gas diffusing in and out of the bloodstream. Fish that live in deep water and never come to the surface tend to be physoclistous but when they are young they come to the surface to fill it for the first time with a gulp of air. They then lose their internal duct, sealing off the swim bladder.

If you are interested, I say more about swim bladders and other fish anatomy topics in my article on Betta Fish Anatomy!

How to Cure Swim Bladder Disease

Swim bladder disease is tricky because there is no one cause for the problem. Fortunately, there are a few things you can do to ease the symptoms or even cure it in your aquarium fish!

Digestive Swim Bladder Disease

If you believe you are looking at a buoyancy issue caused by a digestive disorder then you have a few things you can do. First, you likely need to raise the temperature if you are keeping a tropical fish, like a betta, in cold conditions.

Next there are foods that provide valuable roughage, helping to move any blockages in the guts along to the anus. Cooked peas are widely touted as being a good digestive aid for fish. But only feed peas to omnivorous and vegetarian fish.

Peas are perfect for goldfish swim bladder disease but do not feed peas to betta fish. Bettas are carnivorous and aren’t likely to be interested in peas anyway. Feeding peas to carnivorous fish with digestive issues may even make them worse if all that fiber gets stuck in the short guts.

Instead, you can treat betta swim bladder disease with water fleas (daphnia). They come both live and frozen in many specialty aquarium stores. Water fleas are tiny crustaceans that have a lot of chitinous shell covering their body.

When eaten in large numbers they often have a laxative effect since the shells aren’t digested well. Yet they are mostly digestible protein and loose enough that they won’t cause further impaction in your betta fish!

Swim Bladder Gas Disorders

If your fish has a true swim bladder disorder caused by gas issues there is not a whole lot you can directly do. Some veterinarians do specialize in treating fish, especially large and expensive fish like arowanas and fancy goldfish. They may take a series of x-rays to confirm the disease and then use a surgery needle to de-gas the fish.

This is something you should never do on your own because you’d need to first know where the swim bladder is in your particular fish. And then de-gas it in a way that does not lead to a fatal infection from the wound that is created.

How to Cure Swim Bladder Disease
found on Flickr

Swim Bladder Medicine

If you believe the issue is a bacterial infection though, then medicating the fish with an antibiotic can help get the disease under control. The fish will then remove any internal fluid on its own and recover its buoyancy.

I use API Melafix Aquarium Fish Remedy for bacterial infections. It uses tea tree oil as the active ingredient, a compound that few bacteria are resistant to. It also has the benefit of not impacting your beneficial nitrifying bacteria that make up your biological filtration system!

That said, I always recommend moving sick fish to a separate, smaller quarantine tank. This way, you don’t have to use as much medicine. It is also easier to feed a sick fish, which may have trouble competing with healthy tank mates.

You can adjust other parameters like temperature and add medicines that could be dangerous for scaleless fish, shrimp, and other sensitive tank mates.

We often see bacterial fish bladder disease in aquariums that are allowed to become too dirty. If your fish tank is in need of water changes or the filter is allowed to run without proper maintenance germs can start to thrive.

These germs can eventually overwhelm the immune system of your fish, causing internal infections like swim bladder disease. So I always recommend performing a heavy water change and checking up on any maintenance you may not have been doing.

Is Swim Bladder Disease Fatal?

Fish swim bladder disease can be fatal if it is caused by a fluid buildup, which is often a sign of a deeper infection. Gas disorders aren’t usually fatal from the onset but the longer they last the worse things can become for your fish.


Swim bladder disease is a challenge for aquarists of all skill levels because diagnosing it properly is difficult and time sensitive. And sometimes, no matter if you do everything right, a fish may still end up dying. But with the knowledge you’ve obtained in this guide, you are well equipped to help a fish heal and recover, if at all possible!

More Frequently Asked Questions about Swim Bladder Disease

Why is my Fish Swimming Vertically Head Up?

If your fish is swimming vertically head up it’s probably not a swim bladder disease. It is likely hanging near the surface because oxygen levels in the aquarium have become too low. The signs of a swim bladder disease are floating near the surface on its side, back, or belly. Head up swimming vertically suggests that it is getting as close to rich oxygen as possible.

Why is My Fish Swimming Sideways?

A fish that is swimming sideways may indeed have a swim bladder disease or disorder. Unless it is trying to attract a mate or has specialized fins for this motion, refer to the guide above for diagnosis and treatment options.

How to Treat Swim Bladder Disease

Swim bladder disease treatments depend on the actual cause. If it is due to fluid buildup from a bacterial infection you can use a swim bladder medicine like Melafix to help cure the infection. But actual gas build ups require either time or the help of a vet to de-gas the fish. Digestive issues need time, heat, and a proper laxative to clear the intestinal tract.

Jason Roberts
About Jason Roberts
Jason is an aquarium fanatic that has been a fish hobbyist for almost three decades.