Angelfish Swim Bladder Disorder: Causes, Symptoms & Treatment

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I’ll always remember when I noticed my angelfish showing signs of a swim bladder problem.

The fish looked really troubled – it was swollen, staying near the bottom of the tank, and struggling to swim right.

Luckily, some internet research helped me figure out what was wrong with my angelfish and find a solution.

In this article, I’m going to cover all there is to know about swim bladder disease in angelfish – what causes it, the symptoms, and ways to prevent it.

So, let’s get started.

What Is Swim Bladder Disorder in Angelfish?

Swim bladder disorder in angelfish is a condition where the fish’s swim bladder, an internal gas-filled organ used for buoyancy, becomes impaired.

This can lead to problems with swimming, such as floating upside down or sinking to the bottom of the tank.

It’s often caused by factors like poor water quality, overfeeding, or infections, and requires careful attention to tank conditions and diet to manage or prevent.

Also Read: Angelfish Diseases

What Causes Swim Bladder Disorder in Angelfish?

Swim bladder problems in Angelfish can happen for different reasons, and each one can affect the fish’s ability to stay balanced and swim normally.

1. Poor Water Quality

Angelfish are sensitive to their aquatic environment, and poor water quality is a frequent cause of swim bladder disorder.

Elements like toxic ammonia, fluctuating pH, and temperature changes can adversely affect the swim bladder.

  • Toxin Buildup: High levels of ammonia and nitrites from waste can damage the swim bladder, making proper filtration crucial.
  • pH and Temperature Shifts: Sudden changes in water pH or temperature can stress the swim bladder, highlighting the need for a stable aquatic environment.
  • Identification Tip: Cloudy water or a foul smell are signs of poor water quality.

2. Overfeeding

Overfeeding is a major contributor to swim bladder disorder in angelfish, as it leads to digestive problems that can affect the swim bladder.

  • Digestive Pressure: Excess food intake can cause bloating and constipation, putting pressure on the swim bladder.
  • Nutritional Imbalance: Feeding low-quality or improper food can lead to nutritional issues that impact the swim bladder.
  • Identification Tip: Excess food at the tank bottom or bloated fish appearance indicates overfeeding.

Also Read: Angelfish Constipation

3. Bacterial Infections

Bacterial infections can directly affect the swim bladder of angelfish, resulting in swim bladder disorder.

  • Infection Impact: Bacterial infection can cause inflammation and dysfunction in the swim bladder.
  • Secondary Infections: Infections often arise in poor conditions, leading to bacteria that target the swim bladder.
  • Identification Tip: Unusual swimming patterns and lethargy in fish can be signs of bacterial infection.

4. Physical Injury

Physical trauma is another factor that can lead to swim bladder disorder in angelfish.

Injuries from collisions with tank decorations, aggressive tank mates, or improper handling can damage the swim bladder.

  • Collision Damage: Forceful impacts against tank objects can harm the swim bladder, necessitating a safe tank layout.
  • Aggression Trauma: Fights with other fish can result in injuries affecting the swim bladder, highlighting the importance of compatible tank mates.
  • Identification Tip: Signs of injury, like scrapes or abnormal swimming, suggest possible physical trauma.

5. Genetic Predisposition

Some angelfish may have a genetic tendency towards swim bladder issues.

This predisposition can make them more susceptible to swim bladder disorder, regardless of their environment.

  • Hereditary Factors: Inherited traits can lead to structural abnormalities in the swim bladder, making some fish naturally prone to issues.
  • Selective Breeding: Certain breeding practices can exacerbate this predisposition, especially in line-bred or inbred populations.
  • Identification Tip: A consistent occurrence of swim bladder problems in a specific lineage indicates a possible genetic factor.

What are the Symptoms of Swim Bladder Disorder in Angelfish?

Symptoms associated with swim bladder disorder in angelfish mainly include:

1. Difficulty Swimming Upright

Angelfish with this condition often exhibit a notable struggle in maintaining their buoyancy, leading to a noticeable difficulty in swimming upright.

Observers will typically see these fish laboring to stay level in the water, an effort that should be normally effortless.

2. Swimming Sideways

A distinctive symptom is when the angelfish loses its balance and starts swimming on its side. 

This unusual and unnatural swimming pattern is a clear indication of issues with the swim bladder, which is crucial for maintaining balance.

Also Read: Angelfish Swimming Sideways

3. Bloating

Bloating in angelfish, where their abdomen appears significantly enlarged, is a common symptom.

This swelling is often due to internal pressure in the digestive system, which then impacts the swim bladder, leading to buoyancy issues.

Also Read: Why Is My Angelfish Fat

4. Swimming in Circles

Affected angelfish may display repetitive, uncoordinated swimming behavior, often swimming in circles.

This symptom is indicative of a significant loss of equilibrium and control, pointing to a compromised swim bladder function.

Also Read: Angelfish Swimming In Circles

5. Floating Upside Down

One of the most recognizable signs of swim bladder disorder is when angelfish float upside down.

This unnatural position occurs due to the swim bladder’s inability to regulate buoyancy properly, causing a disorientation in the fish’s orientation.

Also Read: Angelfish Swimming Upside Down

6. Sinking to the Bottom

In some instances, angelfish with this disorder might sink and find it difficult to rise, a sign of a deflated or malfunctioning swim bladder.

This condition leads to the fish spending an unusual amount of time resting on the tank bottom, unable to swim normally.

7. Erratic Swimming

Erratic swimming, characterized by sudden, unpredictable movements, is a symptom of swim bladder disorder in angelfish.

This behavior reflects the fish’s struggle to control its buoyancy and orientation in the water, leading to irregular and frantic swimming patterns.

8. Inability to Swim Up or Down

Angelfish with swim bladder issues often find it challenging to navigate vertically in the water. 

This inability to swim upwards or downwards is a direct consequence of the swim bladder’s compromised function, hindering the fish’s control over its depth.

Also Read: Angelfish Swimming Vertically

9. Lethargy or Inactivity

Lethargy or a noticeable reduction in activity levels can be a sign of swim bladder disorder in angelfish.

Affected fish may show a lack of energy or interest in their surroundings, often staying in one spot due to the discomfort and difficulty in swimming.

How Can You Treat Swim Bladder Disorder

Treating an angelfish with a swim bladder disorder involves several central steps. Here’s what you should do:

1. Improving Water Quality

Addressing swim bladder disorder often involves improving the water quality in your aquarium.

Contaminants like ammonia and nitrite can exacerbate health issues, so maintaining a clean and stable environment is key.

  • Regular Water Changes: Conduct 25-30% water changes weekly, using a siphon to remove debris from the substrate and replenish with dechlorinated water.
  • Filtration System Check: Inspect and clean your filter monthly; replace media like activated carbon or sponges as they lose efficiency, typically every 4-6 weeks.
  • Water Testing: Use a test kit weekly to check ammonia, nitrite, and nitrate levels; aim for ammonia and nitrite at 0 ppm, nitrates below 20 ppm. I found the API Freshwater Master Test Kit (link to Amazon) to be incredibly accurate.
  • Temperature Regulation: Keep the water temperature consistent, within 1-2 degrees of your species’ ideal range, using an aquarium heater and a reliable thermometer.
My API Freshwater Master Test Kit

2. Regulating Feeding Practices

Proper feeding is crucial in managing swim bladder disorder. Overfeeding or a poor diet can lead to digestive issues, affecting the swim bladder.

  • Feeding Frequency: Feed your fish once a day or every other day, depending on their size and species-specific needs.
  • Diet Variation: Offer a mix of high-quality flakes, pellets, and fresh foods; peas are particularly good for aiding digestion in fish.
  • Portion Control: Provide enough food that your fish can consume in two to three minutes, avoiding excess that settles at the tank bottom.
  • Fasting Periods: Implement a 24-hour fasting period once a week to aid in clearing the digestive tract, reducing pressure on the swim bladder.

3. Administering Antibiotics for Infections

If the swim bladder disorder is due to bacterial infection, appropriate antibiotic treatment is necessary.

  • Consult a Veterinarian: Seek advice from a vet specializing in fish; they can prescribe the right antibiotic based on the infection type.
  • Correct Dosage: Follow the prescribed dosage carefully; usually, it involves adding a specific amount of medication per gallon of tank water.
  • Treatment Duration: Complete the full course of antibiotics, typically 7-10 days, to ensure the infection is fully eradicated.
  • Isolation Tank: If possible, treat the infected fish in a separate hospital tank to avoid affecting other inhabitants and to monitor recovery closely.

Also, a good starting point can be over-the-counter products like Seachem PolyGuard (link to Amazon), which treats a wide range of infections.

4. Providing Rest and Isolation for Injury Recovery

In cases where swim bladder disorder is due to physical injury, providing a calm and isolated environment can aid in the fish’s recovery.

Reducing stress and preventing further injury are key factors in this process.

  • Use of a Hospital Tank: Transfer the injured fish to a hospital tank, where it can rest without the stress of competition or aggression from tank mates.
  • Minimal Decor: Keep the hospital tank minimally decorated to reduce the risk of further injury, with soft substrates and no sharp objects.
  • Lower Water Level: Reduce the water level to make it easier for the fish to reach the surface, aiding in buoyancy control and respiration.
  • Gentle Water Flow: Ensure the water flow is gentle to prevent the fish from being tossed around, which can be achieved with an adjustable filter or air stone.

5. Supportive Care for Genetic Cases

When swim bladder disorder is due to genetic predisposition, supportive care focuses on managing the condition rather than curing it.

This involves creating an environment that minimizes stress and addresses the specific needs of the affected fish.

  • Optimized Tank Conditions: Maintain pristine water conditions, as genetically predisposed fish are often more sensitive to environmental changes.
  • Specialized Diet: Offer a diet that’s easy to digest and buoyancy-neutral, like gel-based foods, to reduce the strain on the swim bladder.
  • Stress Reduction: Minimize stress by avoiding sudden changes in the tank, maintaining a peaceful community, and providing hiding places.
  • Regular Monitoring: Keep a close eye on the fish’s behavior and condition, as genetic cases may require adjustments in care over time.

How to Prevent Swim Bladder Disorder in Angelfish

Preventing swim bladder disorder in angelfish involves maintaining optimal tank conditions and ensuring proper care.

Key aspects include quality nutrition, regular water maintenance, and stress reduction to keep your angelfish healthy.

  • Maintain Water Quality: Regularly change 20-25% of the tank water weekly and keep ammonia and nitrite levels at 0 ppm, with nitrates below 20 ppm.
  • Balanced Diet: Feed angelfish high-quality, varied food twice daily, in amounts they can consume in 3-5 minutes to prevent overfeeding.
  • Temperature Consistency: Keep the tank’s temperature stable, ideally between 76-82°F, using a reliable heater and thermometer to monitor.
  • Stress Reduction: Create a peaceful environment with plenty of hiding spots and compatible tank mates to minimize stress-related issues.

Can Angelfish Recover from Swim Bladder Disorder?

Yes, angelfish can recover from swim bladder disorder, especially if it’s caught early and treated appropriately.

Recovery depends on addressing the underlying cause, such as improving water quality or adjusting the diet.

Consistent care and monitoring during treatment significantly enhance the chances of full recovery.

What Is the Fastest Way to Cure Swim Bladder?

The fastest way to cure swim bladder disorder involves a combination of improved water conditions, adjusted feeding practices, and, if necessary, medical treatment.

Ensuring clean, well-oxygenated water and providing a balanced diet are crucial steps. If an infection is present, prompt veterinary consultation for appropriate medication is key.

Can I Use Salt to Treat Swim Bladder Disorder?

Yes, you can use salt in treating swim bladder disorder in angelfish, but it must be done carefully.

Dissolve 1-2 teaspoons of aquarium salt per gallon of tank water and introduce the salt solution gradually over several hours.

It’s important to ensure the salt is aquarium-safe and not table salt, which contains additives. I personally use this API AQUARIUM SALT (link to Amazon).

Can I Feed My Angelfish Canned Peas?

Yes, you can feed your angelfish canned peas, which are helpful for digestive issues often linked to swim bladder disorder.

Make sure to use unsalted peas, and it’s advisable to blanch them for a minute to soften. After cooling, remove the skins for easier digestion.

Offer a small pea or two, chopped into bite-sized pieces, no more than once or twice a week, as part of a balanced diet.

This helps ensure your angelfish gets varied nutrition without overreliance on any single food item.


For quick readers, here’s a short summary:

  • Swim bladder disorder in angelfish is often due to poor water quality, overfeeding, infections, physical trauma, or genetics, leading to buoyancy issues.
  • Symptoms like struggling to swim upright, swimming sideways, bloating, and erratic movements indicate swim bladder disorder in fish.
  • Treating swim bladder disorder involves improving water quality, regulating feeding, and administering antibiotics for infections.
  • Preventative measures include maintaining water quality, providing a balanced diet, and reducing stress in the tank environment.
  • Angelfish can recover from swim bladder disorder with early detection and proper treatment, involving water condition management and dietary adjustments.