Why Is My Angelfish Swimming Upside Down? (5 Quick Solutions)

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I’ll never forget the day I discovered my angelfish flipped over – still alive, but behaving oddly and breathing heavily.

Initially, I was concerned and didn’t know what to do, anxious about the possibility of losing my fish. Fortunately, some quick internet searching came to the rescue, helping me save my angelfish.

In this guide, I’ll cover the reasons angelfish might swim upside down, the methods to correct this issue, and the measures to avoid it happening again. Let’s dive in.

Why Is My Angelfish Upside Down?

Your angelfish being upside down is most commonly a sign of swim bladder disorder.

This condition affects the fish’s ability to control its buoyancy, often due to overfeeding, constipation, or an infection.

It’s important to address the underlying cause and provide appropriate care, such as adjusting the diet or ensuring water quality.

Also Read: Angelfish Swim Bladder Disorder

What Causes Swim Bladder Disorder in Angelfish?

Here are some of the most common causes of swim bladder disorder and consequently an upside-down angelfish:

1. Poor Water Quality

Angelfish are highly sensitive to their water conditions, and poor water quality is a significant stressor that can lead to swim bladder disorder.

Exposure to harmful water conditions affects their overall health, including the function of their swim bladder.

  • High Nitrate Levels: Elevated nitrates can cause stress and physical harm to angelfish, affecting their swim bladder.
  • Unstable pH Levels: Fluctuating pH levels, especially rapid changes, can distress angelfish, potentially leading to swim bladder problems.
  • Toxic Substances: Presence of toxins like ammonia and nitrites, even in small amounts, can cause internal damage, impacting the swim bladder.

2. Overfeeding

Overfeeding is a common issue in aquariums. It not only leads to obesity in angelfish but also causes digestive problems that can press against and impair the swim bladder.

  • Excessive Food Intake: Overeating can lead to bloating and constipation in angelfish, which puts pressure on the swim bladder.
  • Improper Diet: Feeding high-fat or high-protein diets not suited for angelfish can cause digestive issues, affecting the swim bladder.
  • Irregular Feeding Schedule: Inconsistent feeding schedules can disrupt the digestive process, leading to swim bladder disorders.

3. Bacterial Infections

Angelfish can develop swim bladder disorder due to infections caused by harmful bacteria in the water.

These bacteria can infect the swim bladder directly or affect it through other internal organs.

  • Pathogenic Bacteria: Certain bacteria like Aeromonas can infect the swim bladder, causing inflammation and dysfunction.
  • Secondary Infections: Bacterial infections in other parts of the body can spread to the swim bladder, leading to disorders.
  • Compromised Immune System: A weakened immune system due to stress or poor nutrition makes angelfish more susceptible to bacterial infections affecting the swim bladder.

4. Physical Injury

Angelfish can sometimes suffer from physical injuries that affect their swim bladder.

Such injuries might occur due to aggressive tank mates, rough handling, or collisions with tank decorations.

  • Aggressive Tank Mates: Nipping or chasing by aggressive fish can cause physical harm, leading to swim bladder damage.
  • Collision with Objects: Accidental impacts with sharp or hard objects in the tank can injure the swim bladder.
  • Rough Handling: Improper netting or moving of the fish can cause physical trauma, affecting the swim bladder’s functionality.

5. Parasitic Infestations

Parasites can also be a cause of swim bladder disorder in angelfish.

These parasites may directly invade the swim bladder or indirectly affect its function through other internal damages.

  • Direct Infestation: Parasites like nematodes can directly infect the swim bladder, causing inflammation and malfunction.
  • Secondary Health Effects: Parasites living in other organs can cause systemic health issues, indirectly affecting the swim bladder.
  • Stress and Weakness: Parasitic infestations often lead to stress and a weakened state in angelfish, making them more prone to swim bladder issues.

How Do You Treat an Upside-Down Angelfish?

Treating an upside-down angelfish suffering from swim bladder disorder requires a careful and methodical approach. Let’s explore the key strategies:

1. Improving Water Quality

To treat an upside-down angelfish, optimal water quality is crucial. Poor water conditions can exacerbate swim bladder issues by causing stress and deteriorating health.

  • Regular Water Testing: Test the water weekly, maintaining ammonia and nitrite at 0 ppm, and nitrate below 20 ppm, using a reliable aquarium test kit. My recommendation: API Freshwater Master Test Kit (link to Amazon).
  • Frequent Water Changes: Conduct 20-25% water changes every week using dechlorinated water to remove harmful substances and stabilize the environment.
  • Proper Filtration: Install a high-capacity filter suitable for your tank size to ensure efficient removal of waste and toxins, keeping water clean.
  • Temperature Consistency: Maintain a steady water temperature, ideally between 76-82°F, as fluctuations can stress the angelfish and worsen swim bladder issues.
My API Freshwater Master Test Kit

2. Adjusting Diet and Feeding Practices

Dietary changes are essential for managing swim bladder disorder in angelfish. Overfeeding and improper diet are common causes of this condition.

  • Feeding Frequency: Feed your angelfish small amounts twice a day, ensuring they consume all food within a few minutes to prevent overeating.
  • Diet Variation: Include a mix of high-quality flakes, pellets, and occasional fresh or frozen foods like brine shrimp, ensuring a balanced diet. I strongly recommend including these TetraCichlid Cichlid Flakes (link to Amazon) in their diet.
  • Pea Treatment: Offer a cooked, peeled pea once a week to aid in digestion and prevent constipation, a common cause of swim bladder disorder.
  • Avoid Floating Foods: Choose sinking pellets over floating ones to prevent your angelfish from swallowing air while eating, which can affect the swim bladder.

Also Read: Why Is My Angelfish Fat

3. Antibiotic Treatment for Bacterial Infections

If the swim bladder disorder is due to a bacterial infection, antibiotic treatment may be necessary under veterinary guidance.

  • Veterinary Consultation: Consult with a veterinarian experienced in fish health to diagnose bacterial infections accurately.
  • Appropriate Antibiotics: Use antibiotics prescribed by the vet, such as Maracyn or Kanaplex, following the specific dosage and duration instructions.
  • Quarantine Treatment: Treat the affected angelfish in a separate quarantine tank to avoid impacting other fish and monitor the response to medication.
  • Post-Treatment Care: After antibiotic treatment, gradually reintegrate the angelfish into the main tank, observing for any signs of relapse or other health issues.

4. Reducing Stress and Isolation

Stress management is key in treating swim bladder disorder in angelfish, especially if the condition is caused or exacerbated by stress.

  • Gentle Handling: When interacting with your angelfish, be gentle to avoid additional stress that can worsen the swim bladder condition.
  • Peaceful Environment: Create a calm tank environment with minimal noise and light disturbances to help the angelfish relax and recover.
  • Isolation if Necessary: If aggression from tank mates is a stress factor, temporarily isolate the affected angelfish in a separate, well-equipped tank.
  • Enriched Habitat: Provide ample hiding places and a comfortable habitat in the tank to make the angelfish feel secure and reduce stress.

5. Treating Parasitic Infestations

If a parasitic infestation is contributing to the swim bladder disorder, specific treatments are required to address these parasites.

  • Accurate Diagnosis: Have a vet or a fish health expert diagnose the specific type of parasitic infestation using stool samples or visual inspection.
  • Appropriate Medication: Use anti-parasitic medications, such as Fritz Mardel Coppersafe (link to Amazon) or Metronidazole, as directed for the specific type of parasite identified.
  • Water Quality Maintenance: During treatment, maintain excellent water quality, as parasites often thrive in poor conditions, which can further stress the fish.
  • Follow-up Care: Continue monitoring water quality and the angelfish’s health post-treatment to ensure the complete eradication of parasites and prevent recurrence.

Can Angelfish Recover from Swim Bladder Disorder?

Yes, angelfish can recover from swim bladder disorder.

With proper treatment addressing the underlying cause, such as improving water quality, adjusting diet, or treating infections, they can regain their buoyancy control.

Consistent care and monitoring are crucial for their full recovery and preventing future occurrences.

How Can I Prevent Swim Bladder Disorder in My Angelfish?

Preventing swim bladder disorder in angelfish involves maintaining optimal tank conditions and careful feeding practices.

Regular monitoring and proper care can significantly reduce the risk of this condition affecting your fish.

  • Maintain Water Quality: Keep ammonia and nitrite levels at 0 ppm, and nitrate levels below 20 ppm, with regular testing and 20-25% weekly water changes.
  • Balanced Diet: Feed your angelfish a varied diet including high-quality flakes, pellets, and occasional fresh or frozen foods, avoiding overfeeding.
  • Reduce Stress: Create a calm environment with adequate hiding spaces and a stable routine to minimize stress that can lead to swim bladder issues.
  • Regular Health Checks: Observe your angelfish regularly for any signs of abnormal swimming or buoyancy issues, acting promptly to address any health concerns.

What Are Some Less Common Causes of an Upside Down Angelfish?

Less common causes of an upside-down angelfish can sometimes be attributed to factors like neurological conditions, age-related issues, or, unfortunately, the fish being deceased.

1. Neurological Conditions

Neurological issues in angelfish can disrupt their balance and coordination, leading to upside-down swimming. These may arise from genetic anomalies, infections, or injuries.

  • Identification: Notice signs like erratic swimming, spinning, or difficulty maintaining upright position, which are indicative of neurological issues.
  • Veterinary Consultation: If neurological issues are suspected, seek advice from a fish health expert or vet for diagnosis and potential treatments like medication.
  • Supportive Care: Ensure a stress-free tank environment with optimal water quality and a balanced diet to support the angelfish’s overall health.

2. Age-related Weakness in Senior Angelfish

As angelfish age, they might face challenges with swimming due to muscle or organ weakness, including the swim bladder.

  • Identification: Observe older angelfish (typically over 3 years) for signs of lethargy or swimming difficulties, common in age-related weakness.
  • Adjusted Environment: Create a tank setup with more resting spots and gentle water currents to accommodate the reduced mobility of older angelfish.
  • Specialized Diet: Offer soft, easily digestible foods and possibly hand-feed if necessary, to ensure the senior angelfish maintains adequate nutrition.

3. Deceased Angelfish

Sometimes, an angelfish swimming upside down could indicate it has passed away, which is a natural occurrence in aquariums.

  • Identification: Check for lack of gill movement and response to stimuli; a deceased fish will not respond and will often float upside down.
  • Prompt Removal: If the fish is deceased, remove it from the tank immediately to prevent water contamination and stress to other fish.
  • Post-Removal Care: After removing the deceased fish, monitor water parameters and the health of other tank inhabitants for any signs of disease or stress.


For quick readers, here’s a short summary:

  • Angelfish swimming upside down is commonly due to swim bladder disorder, often caused by factors like poor water quality, overfeeding, or bacterial infections.
  • Maintaining optimal water quality, including regular testing and water changes, is crucial for treating and preventing swim bladder disorder in angelfish.
  • Dietary adjustments, such as feeding high-quality food in appropriate amounts and avoiding overfeeding, are essential for managing swim bladder issues.
  • For swim bladder disorders caused by bacterial infections or parasitic infestations, specific treatments like antibiotics or anti-parasitic medications are necessary.
  • Stress reduction and creating a peaceful tank environment can significantly help in the recovery and prevention of swim bladder disorder in angelfish.