Why Is My Betta Fish Swimming Sideways? (+ Swim Bladder Disease Signs)

Wondering why your betta fish is swimming sideways? This guide is for you!

New betta hobbyists may be alarmed to see their betta fish swimming sideways. However, the more seasoned betta keepers are unlikely to panic because they know the cause.

Your betta fish swims sideways because its swim bladder has been compromised. In other words, disease or poor tank conditions affect your betta’s mechanism to maintain and control buoyancy. As such, this animal cannot swim in a straight position and is forced to swim sideways.

The important thing when you notice this is to get a hold of yourself and focus on helping your pet betta. Do not panic; this situation has a solution.

betta fish swimming sideways

Why Do Betta Fish Swim Sideways?

You should be concerned when your betta fish starts swimming sideways. This abnormal behavior indicates the possibility of swim bladder disease or other health complications.

Your first reaction should not be to panic, as this will likely worsen things. Instead, get a hold of yourself and look for the cause(s) of this abnormal behavior.

Here are a few reasons your betta fish is swimming sideways:

Temperature Fluctuations

Betta fish originated in the warm tropical climates of South East Asia. Therefore, they are well-balanced and adjusted in warm water.

Your betta fish prefers to live in tank water temperatures between 240C and 280C (760F and 820F). Your pet will be in trouble if the water temperature falls below the lower reading.

Betta fish face severe hardships when made to stay in cold water. Besides this stress, the betta fish becomes lethargic and cannot control its movements properly.

Your betta fish will find it hard to swim upright and start swimming sideways. This animal will not be able to swim at all if the temperatures keep dropping further.

To prevent this from happening and correct this fish’s swimming posture, you need to raise the water temperature to the acceptable range.

Dirty Water

Take a close look at the tank water to verify its cleanliness. Remember, some of the things that compromise the water quality cannot be seen with the naked eye.

Being very sensitive animals, bettas are easily affected by changes in water quality. A significant change can make your betta fish disoriented to the extent it swims sideways.

Changing about 30-40% of the tank water is the solution. Then, replace this water with conditioned, clean water and observe how your pet betta behaves.

If it swims normally, you can be sure the unclean water is the cause of the problem.

Poor Water Parameters

Are the water parameters in the tank ok? Bad water parameters are a major cause of poor swimming posture in betta fish.

Check for the levels of ammonia, nitrates, nitrites, and pH using quality test kits. This should tell you whether the water is fit for your pet or not.

The ammonia and nitrite levels should be at 0 ppm, while the ideal pH level should stand between 6.5 and 8.5.

If the water parameters are poor, quickly change the water and clean the tank. Also, use a good water conditioner to get rid of any toxins in the water.

After this, carefully monitor your betta’s movement. For example, has it stopped swimming sideways?

Swim Bladder Disease

This can be said to be the most serious cause of your betta swimming sideways. We have left it for last so we can discuss it in detail.

Swim bladder disease is a condition that affects the swim bladder of bettas and other types of fish.

Though there are many swim bladder disorders, the swim bladder disease is most likely to cause your betta to swim sideways.

This disease is caused by a bacterium that attacks your betta swim bladder. This vital organ helps this fish with control, balance, and buoyancy.

This problem needs to be sorted out immediately to save your betta fish from further complications.

What is Swim Bladder Disease?

The swim bladder allows betta fish to swim upright and horizontally in the water. The swim bladder is filled with gas that enables the float as the fins propel it forward.

If too much gas finds its way into the swim bladder, it is expelled through a thin tube into the intestine.

This allows the betta fish to control its buoyancy and swimming direction. However, when the swim bladder has been compromised by disease, this system does not work correctly.

What Are the Signs of Swim Bladder Disease?

Swim bladder disease makes the fish swim around the tank awkwardly, with the most noticeable abnormality being swimming sideways.

Betta fish with swim bladder disease display a number of other abnormalities. These include swimming with difficulty, swimming in a darting motion, and having an S-shaped spine.

Swim bladder disease could also force the fish to sink into the bottom of the tank or float at the water’s surface.

Quick actions should be taken to treat this disease if you hope to save your pet betta.

What Causes Swim Bladder Disease?


Constipation is a common cause of many health complications in bettas and other fish. For example, it is responsible for many cases of swim bladder disease.

Constipation makes it hard for your betta fish to pass stool. As such, the intestines become swollen and pile pressure on the swim bladder.

This makes it hard for the fish to expel any excess gas in the swim bladder. If the fish does not get timely relief, the accumulated gas makes the betta develop swim bladder disease.

The fish finds it challenging to swim upright or adequately navigate through the tank.

Stomach Distress

If your betta fish experiences physical trauma to the stomach, its swim bladder is likely to be affected.

This is one of the reasons it is essential to handle your bettas gently as you clean the tank. Trauma that raptures the swim bladder often leads to swimming bladder disease.

It may require the intervention of a surgeon to put everything back together for your betta to regain his health.

Ironically, abdominal surgery has been responsible for swim bladder disease in cases where the surgery was done for something else.

Ingesting Too Much Air

Bettas are labyrinth breathers with specialized organs that allow them to gulp air for the surface.

This is quite useful when the oxygen level in the water is low.

But, bettas often get into trouble when they ingest too much air at a go from the surface. Surface air is not harmful if taken in moderation but causes problems when taken in excess.

The situation is worsened if the betta fish ingests too much air while swallowing food simultaneously. This is one of the things that cause swim bladder disease.

Bacterial and Viral Infections

A good number of swim bladder disease cases emanate from viral and bacterial infections. This comes about when your betta fish is made to live in unhygienic conditions.

Viruses and bacteria can also come from poor food supplies, new tank mates, and improper handling of betta fish and tank equipment.

Bacterial infection compromises your betta’s immunity and makes him vulnerable to all kinds of opportunistic infections.

Suppose your betta has peripheral issues in the stomach, intestines, or swim bladder. In that case, he will easily get swim bladder disease because of compromised immunity.


Betta fish can get tumors on any part of the body. However, a good number of bettas get tumors in the tailfin.

If the tumor happens to be in their swim bladder, the bettas swimming control and sense of direction become compromised.

If your betta starts swimming sideways, it could suffer from swim bladder disease caused by tumors.

This is one of the most serious health issues your betta fish can fish. Unfortunately, in most cases, there’s nothing much you can do to a betta fish with this condition but euthanize it.

How to Cure and Treat Swim Bladder Disease

Swim bladder disease is preventable if you keep your betta safe and handle him with care. Fortunately, this disease can also be treated in most cases.

As with all diseases and health conditions, the sooner you start treating swim bladder disease, the better for your pet.

Swim bladder disease can be treated in a number of ways:

Clean the Tank

Swim bladder disease is often caused by unclean water in the tank. This means you can prevent and control this disease by keeping your betta tank clean.

Change the tank water at least once a week by removing 30-40% of the water and replacing it with clean, conditioned water.

If your betta fish already has swim bladder disease, aid it in getting better by thoroughly cleaning the tank.

Clean everything in the tank, including the decorations, plants, and gravel. Doing a thorough job of this removes all parasites and chemicals that could be causing swim bladder disease.

Additionally, check the water and pH levels to ensure everything is up to standard. The water should neither be too hot nor too cold.

Provide Quality Food

Giving your betta fish quality food consistently builds up their immunity. In addition, your bettas thrive on a high-protein diet that enables them to have a healthy, well-functioning swim bladder.

The right protein content enables this fish to expel excess gas from the swim bladder, making it easy for your fish to swim properly.

When the betta fish starts to recover from the swim bladder disease, gradually wean them off the high-protein diet.

This is because high-protein diets are also high in fat, which might lead to problems of obesity.

Use the Right Antibiotics

The use of antibiotics is a powerful way of controlling the progression of swim bladder disease. However, you need to seek the advice of your vet before dispensing any antibiotics.

This is because antibiotics are likely to cause more harm than good if misused. Also, antibacterial treatments do not distinguish between good and bad bacteria.

They also kill the bacteria in your betta tank; use them advisedly.

Some of the antibiotics that have been proven to cure swim bladder disease include Nitrofurazone, Neomycin, Bacitracin, Tetracycline, and Kanamycin.

Use Epsom Salt

Using Epsom or aquarium salt is an excellent way of helping your betta fish expel excess gas from the swim bladder.

Used properly, this treatment enables your betta fish to recover quickly from swim bladder disease.

Add one teaspoon of aquarium or Epsom salt to every gallon of water in the betta tank. Notably, this is the quarantine tank you have put the betta infected with swim bladder disease.

Seasoned hobbyists believe you can use Epsom salt in the main tank if it doesn’t have plants or snails. However, to play it safe, it’s best you apply this treatment in an isolation tank.

Epsom or aquarium salt should not be used unless your pet suffers from this condition. Using this salt frequently on healthy bettas may be counterproductive in the long run.


This invasive procedure should be used when there’s no other way out. For example, your vet will recommend surgery if your betta’s digestive system is clogged or blocked.

This procedure allows the betta to release excess air from the swim bladder. Also, it removes the problems causing air retention in this organ.

How Do You Prevent Swim Bladder Disease?

Suppose you can prevent swim bladder disease from infecting your betta fish. In that case, you won’t have to witness the agony of this fish swimming sideways.

Here are a few tips to prevent this disease:

Isolate New Fish

Swim bladder disease may start when new fish introduce strange parasites into the tank. You can circumvent this problem by ensuring that all new fish are quarantined.

Isolate them for two weeks and closely monitor them for diseases and infections.

Provide Quality Food

Constipation comes about because of a poor diet. So your betta fish requires a high-quality diet rich in protein and fiber.

Source your betta food from a reputable supplier – those you know are unlikely to compromise the quality of your betta food.

Don’t Overfeed Your Betta

Bettas keep eating as long as the food is available. If this is not checked, they soon develop constipation and stomach bloating.

The swollen intestines push against the swim bladder, effectively blocking excess air from escaping. This is one of the significant causes of swim bladder disease.

By not over-feeding your betta fish, you ensure that its digestive system continues to function optimally.

Regularly Change the Water

Changing the water at least once a week ensures that toxins are eradicated before they harm your betta fish.

Since contaminants are one of the significant causes of swim bladder disease, changing the tank water is advantageous for your betta fish.

High Standards of Hygiene

Betta fish are very sensitive to dirt and unclean water.

Keeping your betta in unclean conditions is likely to trigger all kinds of parasitic attacks, leading to swim bladder disease and other health conditions.


There are a number of factors that may cause your fish to swim sideways. The most serious of them is swim bladder disease, a condition characterized by air retention in the swim bladder.

A betta fish with this problem appears bloated and floats to the top of the tank, or swims crookedly.

Fortunately, with the correct tank practices and medical management, swim bladder disease is preventable, curable, and treatable.

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