Why is Betta Fish Swimming Sideways (Swim Bladder Disease)?

Betta fish are entertaining and active fish to keep in a fish tank. Their vibrant hues and behavior make them the life of the party in an ordinary aquarium.

However, if you notice your Betta fish swimming sideways, then there is a high chance that it may be suffering from Swim Bladder Disease.

Most fish are not meant to swim sideways or float at the top and bottom of the tank.

A healthy Betta fish should be swimming around in the middle section of the tank. Hence, a Betta on its side might indicate a problem.

Let’s dive into the specifics of Swim Bladder Disease and why your Betta fish is swimming sideways.

What is Swim Bladder Disease?

Swim Bladder Disease is a disorder common in Betta fish.

It includes the swelling of the swim bladder, which eventually messes with the buoyancy of your Betta fish.

The swim bladder is found beneath the Betta fish’s internal organs. Its health is essential because it helps the fish swim in the water.

In other words, the swim bladder is a Betta fish’s swimming mechanism. Without a healthy swim bladder, fish cannot swim in the water normally.

It can simply appear as bloating, which leads the fish to swim lopsided or float to the top of the fish tank.

Why is Your Betta Fish Swimming Sideways?

Since the buoyancy of your Betta fish is compromised, it is no longer able to maintain a straight position to swim in the water.

Instead, the swollen swim bladder throws the Betta fish off balance, forcing it to swim sideways or oddly.

In some cases, you may notice the Betta fish floating on the top of the tank due to the bloated swim bladder.

Since the bloated swim bladder may be full of air, it becomes difficult for the Betta to regain control of its movements.

Symptom Check for Swim Bladder Disease in Betta Fish

If your Betta fish is suffering from Swim Bladder Disease, you may notice the following symptoms:

  • A bloated belly
  • Odd swimming patterns
  • Curved spine
  • Struggle in maintaining one position for long
  • May dip to the substrate level of the tank
  • Lethargy
  • Lack of appetite
  • Trouble eating food

If you feel your Betta fish is showing at least two or more of these symptoms, it might be suffering from Swim Bladder Disease and should be treated immediately.

What’s Causing It?

Several factors can cause Swim Bladder Disease in Betta fish.

Knowing the cause behind your pet’s sickness will help you eliminate the root cause so the disease does not become a recurring pattern.

Here are all the causes that may cause Swim Bladder Disease in Betta fish:

Tank Water Temperature

Betta fish, just like most small fish species, are incredibly delicate creatures. They require a lot of attentive care from the owner to survive and stay healthy.

The water temperature in the tank plays an integral role in keeping the Betta fish healthy.

They are incredibly sensitive to temperature changes because their body is meant for a stable water environment. 

Betta fish require a water temperature of 75–80 degrees Fahrenheit. If the temperature is less or more than this criterion, it can be detrimental to the Betta fish’s health.

If you live in a warm climate, there is a chance that you can keep the water tank naturally warm for the Betta fish to survive.

However, if you live in a cold climate, you should invest in a water tank heater to maintain the ideal temperature suited for your pet’s needs.

You need to note that even when you have a water tank heater installed, you should always check the temperature in your routine checks to make sure that everything is fine.

Since the water tank heater is a machine, it can sometimes stop working.

This can cause water temperature surges and can be incredibly stressful for a Betta fish.

Moreover, cold water temperatures can cause several diseases in Betta fish, out of which Swim Bladder Disease is the most common one.

Tank Water Quality

Apart from water tank temperature, another thing that can cause Swim Bladder Disease is the quality of water that the Betta fish live in.

You must filter the tank using a high-quality filtration system not to build bacteria buildup in the water tank.

Other than this, you should clean and cycle the tank as frequently as possible to keep everything clean and germ-free.

Every time you add something to the tank, such as a plant or a decoration piece.

It is essential you thoroughly clean and disinfect each piece as it may carry bacteria or parasites.

Similarly, you should only feed your Betta fish superior quality food because there are chances of live foods being infected with deadly bacteria and parasites that can contaminate the water.

Dirty water or water with a high chemical percentage can also be incredibly harmful to a Betta fish.

Hence, to keep your Betta fish healthy and avoid diseases like Swim Bladder Disease, you need to provide your pet fish with clean water that has been fully treated for chemicals.

Parasites & Bacterial Infections

Bacteria growth or parasites in your Betta fish’s living space can be harmful because they directly attack the stomach and intestinal areas.

This is why it can be one of the causes of Swim Bladder Disease.

Usually with infections, Betta fish appear incredibly slow and sluggish in their movements apart from swimming sideways.

The bacterial growth makes it hard for them to swim around normally or stay in one position for a more extended time.

All bacterial infections and parasitic attacks aren’t fatal for Betta fish, but there is always a chance of getting worse. This is true, especially if there are a lot of bacteria in the fish tank water.

Chances of survival in Betta fish become incredibly low if the Swim Bladder Disease situation gets out of hand.

Bacterial infections treated in the early stages can be easily cured, but once they get out of hand, putting your Betta fish down is the only option.

Therefore, maintaining water quality is crucial to prevent Swim Bladder Diseases and other conditions that can be harmful to Betta fish.


If you are a Betta fish owner, you probably already know how much Betta fish like to eat.

Since they are carnivorous creatures, eating is one of the things they enjoy the most.

However, due to their love for food, overeating is a common factor that can cause Swim Bladder Disease in Betta fish.

When they eat more than is intended for their little bellies, it is easy for them to swell up.

This harms the swim bladder leading to lopsided swimming and other odd movements.

Be careful about how many times you are feeding your Betta fish in a day to prevent diseases such as Swim Bladder Disease.

Air Gulps

Another issue related to overfeeding is when Betta fish accidentally gulp air while consuming the food from the tank’s surface.

The air bubbles cause the swim bladder to swell up, which results in discomfort and sideways swimming.

The more food Betta fish consume the more air bubbles fill into the swim bladder.

This also happens if your pet fish has been hungry for a long time and you are late with food delivery.

Hunger can cause them to gulp more air to consume the food on the surface quickly.

Try to control your betta fish’s meals in quantity and pace them out during the day in a manner where they do not go hungry for an extended period.


It is very easy to shock or stress out a Betta fish. Loud noises, reflections in the mirror, excessive light, and temperature changes are just a few of the causes that can lead to stress in a Betta fish.

Stress or shock can make a Betta fish prone to diseases and sickness, just like the Swim Bladder Disease.

Betta fish are incredibly fragile creatures, which is why it is essential to take care of their needs appropriately.

It’s important for you to find out the reason for their shock or stress and make sure you take care of it. If left unchecked, the stress in fish can lead to a lot of other issues, such as loss of appetite and low immunity (which makes them prone to infections)

Kidney Problems

Kidney cysts or other kidney problems can also be an underlying cause for Swim Bladder Disease in Betta fish.

Even though this factor is pretty uncommon, it is still possible.

If kidney problems are why your Betta fish has Swim Bladder Disease, then there isn’t much that can be done about the situation.

The Final Word

Any kind of odd movements in swimming is an alarming sign for fish owners.

If you notice your Betta fish swimming sideways or floating at the top, do not waste time determining the underlying cause.

Once you figure out what may be making your fish sick, you can take a step towards treating your Betta fish.

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