Betta Fish Swimming Sideways: Treatments & Reasons

Illustrating a dazzling array of splendid colors, Betta, or the Siamese Fighting fish, are intelligent creatures that inhabit the slow-moving waters of Thailand, Cambodia, Indonesia, and Vietnam. 

However, the Bettas living in the artificial waters result from selective aesthetics-based breeding. Like any living thing, your Betta may also fall victim to illness, potentially exhibiting symptoms like swimming sideways due to compromised buoyancy.

In this article, we’ll discuss reasons why your Betta may be swimming sideways, discuss swim bladder disease, and provide a few tips to help cure it. 

Reasons for My Betta Swimming Sideways

Betta Fish

While Bettas are playful and interactive creatures always exploring the environment and often exhibiting unusual movements, swimming sideways for a prolonged period isn’t among their display of acrobatics.

Let’s discuss the reasons that may cause it:  

Genetic Defects

Bettas bred from a small gene pool or through poor breeding practices may inherit genetic defects affecting their swimming pattern. It can be caused due to an asymmetric fin structure, poor eyesight, and malformation of the swim bladder. 

In most genetic cases, the signs usually appear shortly after Betta fry becomes free-swimming. They might struggle to float, fail to maintain a normal swimming posture or sink to the bottom.

Bettas with genetic swim bladder disease may not respond to typical treatments for the same. If your Betta is still swimming sideways despite treatments, consult your vet to consider your options, including euthanization. 

Also Read: Betta Sorority Tank Setup Guide

Physical Injury

Bettas are quite susceptible to physical damage and trauma due to their small and feeble body, In addition to being harmed in the fins or the spine, a blow to the swim bladder may damage the organ and permanently affect the swimming posture and balance. 

Damage to the muscles or the nervous system may also impair your Betta’s ability to swim normally. This type of injury usually occurs due to improper handling and tank accidents. This may include rough handling during maintenance, jumping out of the tank, injury from sharp decorations, and aggressive tank mates. 

Behavioral changes, such as lethargy, reduced appetite, or hiding behavior, may accompany the trauma. 

Water Quality Issues

Fish waste, uneaten food, and decomposing plant matter produce huge amounts of ammonia. The ammonia is toxic to fish and might cause internal damage if the concentration is beyond tolerable levels. This may leave your Betta with organ damage, resulting in erratic behavior, sideways swimming, and even death. 

Nitrite, converted from ammonia by beneficial bacteria during the nitrogen cycle, also exhibits similar symptoms and hinders your Betta’s ability to absorb oxygen. 

Incorrect pH levels due to the introduction of tap water, tank substrates, and decorations can cause stress, affecting your Betta’s overall health and swimming behavior. 

Poor water quality may also trigger bacterial outbreaks, adversely affecting the swim bladder and causing permanent damage. 

Water Temperature Issues

Bettas, similar to other fish, are cold-blooded animals, Excessively high and low temperatures can affect their metabolic rate and cause physiological issues. Sudden or prolonged exposure to inappropriate temperatures can develop swim bladder dysfunction and sideways swimming.

Additionally, inadequate heating and colder temperatures slow down metabolism and digestion, making Bettas lethargic and constipated. This may sometimes cause erratic swimming. 

Overheating, on the other hand, increases metabolic rate excessively. This leads to stress, reduced oxygen levels, erratic swimming, and potential swim bladder disease. 


When your Betta fish is constipated, the buildup of fecal matter in their digestive tract can put pressure on the swim bladder, affecting its ability to regulate buoyancy properly. this, in severe cases, may cause upside-down floating and sideways swimming.

Symptoms of constipation may include:

  • Infrequent or reduced bowel movements or small, dry, and stringy feces.
  • Your Betta fish may show reduced interest in food or may refuse to eat altogether.
  • Constipated Betta fish may appear lethargic, spending more time resting at the bottom of the tank or near the surface.

For the most part, swim bladder disease is the reason behind your Betta swimming sideways. Let’s discuss what it is. 

Also Read: How Long Can Betta Fish Go Without Food?

What is Swim Bladder Disease?

Betta Swim Bladder Disease

The swim bladder is a gas-filled internal organ that acts like a buoyancy control device, helping fish stay at their desired depth in the water without constantly having to swim. Swim bladders in most fish are quite flimsy and often get damaged by slight trauma or stress.  

Swim bladder disorder, also known as swim bladder disease or flipover, is a condition affecting your Betta’s swim bladder. When it malfunctions, your Betta may lose control of their buoyancy and experience difficulty swimming normally. 

The symptoms of swim bladder disease involve: 

  • Floating: This is a classic sign. Your Betta may float uncontrollably at surface level, sometimes even upside down. It may struggle to stay submerged or swim downwards to collect food or explore the tank.
  • Sinking: In malfunctions, Bettas with swim bladder disease will sink to the bottom and struggle to hold position. They may appear lethargic and have difficulty reaching the surface.
  • Tilting or listing: Your Betta might also have trouble maintaining a horizontal position and appear tilted to one side or swimming erratically. They may list or roll as they attempt to navigate the water.
  • Strained swimming: Fish, including Bettas, with swim bladder issues may appear to be working extra hard to swim normally. Their movements may be jerky, labored, or unbalanced.
  • Loss of appetite: Swim bladder disease can be stressful and painful for your Betta, leading to a loss of appetite. They may refuse food or show little interest in eating.

We’ve already discussed the reasons behind sideways swimming, including swim bladder disorder. Now, let’s take a look at how it develops in Bettas. 

Also Read: Elephant Ear Betta Care Guide: Diet, Diseases, Tank Set-Up And More

How does Swim Bladder Disease develop in Bettas?

Swim Bladder Disease develop in Bettas

Here are the ways swim bladder disease develops in Bettas: 


Bacterial and parasitic infections can inflame or damage your Betta’s swim bladder and cause buoyancy issues. Pathogens, such as Aeromonas and Pseudomonas, can infect the swim bladder, causing inflammation and sideways swimming. If accidentally introduced, internal worms or protozoans can invade the swim bladder and surrounding organs. They can cause physical damage and cause inflammation to your Betta’s swim bladder. 


Bettas develop both malignant and benign tumors. If the development is near the swim bladder, it can exert pressure on the organ and cause it to function improperly, leading to buoyancy issues. Malignant tumors not only obstruct the swim bladder’s function but can also spread to other organs and affect your Betta’s ability to swim properly. 

Overfeeding and Constipation

Bettas have a very small stomach that can easily be overfed and lead to constipation. This is most prevalent among beginner aquarists who don’t yet have an idea of proper portion sizes and nutritional requirements for Betta. The undigested food can expand within the digestive tract and press against the swim bladder to cause temporary discomfort. 

Constipation, in contrast, can be caused by a diet that lacks fiber. It may block the intestine and create pressure on the swim bladder. A distended belly and sideways swimming are typical signs of constipation. 

Air Ingestion

Bettas have a labyrinth organ that allows them to breathe atmospheric air. However, excessive gulping at the surface due to poor water quality or feeding techniques can lead to air being trapped in the digestive system and causing swim bladder disorder.

Feeding floating pellets can sometimes cause Bettas to gulp air while eating. Pre-soaking pellets or feeding sinking foods can help reduce the risk of air ingestion and subsequent buoyancy issues.

Also Read: Live Betta Fish Plants: The Ultimate Guide

How to Cure Swim  Bladder Disease? 

Swim  Bladder Disease

While there’s no single “cure” to swim bladder disorder, a comprehensive approach addressing the underlying cause offers the best chance of recovery. Here’s a detailed breakdown of various treatment methods:

Improve Water Quality

Perform water changes of 25-50% of the tank volume 2-3 times a week. This dilutes ammonia, nitrite, and nitrate, all of which can stress fish and exacerbate swim bladder problems.

Use a test kit to monitor water parameters like pH, ammonia, nitrite, and nitrate. Ensure they fall within the optimal range. For example, your Betta should thrive in a pH range of 6.8-7.5 with minimal ammonia and nitrite levels and nitrates below 40 ppm.

Clean or replace filter media regularly to maintain proper biological filtration. This ensures the efficient removal of nitrogenous waste products that can deteriorate water quality. Moreover, ensure adequate aeration, especially in smaller Betta tanks. Increased oxygen levels can improve overall health and potentially aid digestion, which, as mentioned, can benefit swim bladder function in some cases.

Adjust Diet and Feeding

If overeating or constipation has occurred, withhold food for 2-3 days, allowing the digestive system to clear any blockage and reduce stress on the swim bladder. After the fasting period, offer a small piece of blanched and deshelled pea to your Betta. The soft texture is easy to digest and can help alleviate constipation.

When the conditions have improved, switch to smaller portions of high-quality food. Feed 2-3 times a day instead of one large feeding. This reduces the risk of overeating and air gulping, which can disrupt swim bladder function.

Get Your Betta From Ethical Breeders

While not a direct treatment method, purchasing Bettas from reputable breeders who prioritize selective breeding and proper tank conditions can minimize the risk of genetic swim bladder disease in the long run. They also breed from a larger gene pool to avoid circumstances exactly like this. These breeders are more likely to produce Bettas with healthy body shapes and fewer internal abnormalities that might predispose them to swim bladder problems.

Consider Environmental Adjustments

For Bettas, raising the water temperature slightly (within a safe range) can aid digestion and improve swim bladder function. If your tank has a strong current, consider reducing the flow rate as it can make swimming difficult for your Betta with swim bladder issues and add to their stress levels.

Salt Treatment

In mild cases, a short Epsom salt bath can sometimes offer temporary relief from constipation and bloating. Dissolve 1 tablespoon of Epsom salt per gallon of tank water in a separate container. Bathe your Betta for 15-30 minutes while monitoring it closely. 

Adding a low dose of aquarium salt (around 1 teaspoon per 5 gallons) to the main tank can improve swim bladder function and potentially offer some relief. However, be cautious as excessive salt can be harmful to freshwater fish like your Betta.

Administering Medication

In cases where a bacterial infection is suspected as the cause of swim bladder disease, antibiotic medication may be necessary.  

Some antibiotics that are often prescribed include: 

  • Oxytetracycline
  • Ciprofloxacin
  • Enrofloxacin
  • Kanamycin
  • Sulfamethazine

However, antibiotics should only be administered under the guidance of a qualified fish veterinarian. 


Surgery to address swim bladder problems is a very delicate procedure and is generally considered a last resort due to its high-risk nature. It’s typically only attempted by experienced fish surgeons.

Also Read: What Can Betta Fish Eat Of Human Food? (Ultimate List)


Q: What does it mean when my betta fish is swimming on its side?

It usually means that your Betta fish may have developed some internal complications, including infections, tumors, constipation, and swim bladder disease.

Q: How to fix swim bladder in betta?

Improving water quality and adjusting diet are the most typical treatments for temporary swim bladder disorder. While there is no cure for genetic buoyancy issues, antibiotics, salt baths, and surgery can improve some acquired conditions.

Q: Why isn’t my betta fish swimming straight?

If your Betta fish isn’t swimming straight, it may have developed swim bladder disorder. Avoid overfeeding and fast your Betta for a few days before consulting your vet about the issue.

The Bottom Line

Betta fish swimming sideways can be attributed to various underlying issues, including swim bladder disease, infections, poor water quality, and dietary problems. We’ve discussed the symptoms and the treatment process for the same. Timely intervention and diligent care can help restore normal swimming behavior and prevent future occurrences.

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