Betta fish, with their vibrant colors and elegant fins, are a popular choice among aquarium enthusiasts. However, like all fish, bettas are susceptible to various diseases. Recognizing and treating these ailments early can make a significant difference in the health and longevity of your betta. Here are some of the most common diseases that affect betta fish, along with their symptoms, causes, and treatments.

1. Fin Rot


  • Ragged or frayed fins
  • Blackened or reddened fin edges
  • Fins may appear to be disintegrating

Causes: Fin rot in betta is typically caused by bacterial infection, which can result from poor water quality, stress, or injury.


  • Improve water quality through regular water changes and proper filtration.
  • Use antibacterial medications specifically designed for fin rot.
  • Ensure the tank is clean and free of sharp objects that could cause injury.

2. Ich (White Spot Disease)


  • White spots on the body and fins
  • Rubbing against objects in the tank (flashing)
  • Lethargy and loss of appetite

Causes: Ich is caused by a parasitic protozoan, which can be introduced through new fish or plants.


  • Raise the water temperature gradually to 80-82°F to speed up the parasite’s life cycle.
  • Use ich-specific medications available at pet stores.
  • Quarantine new fish and plants before adding them to the tank.

3. Velvet (Oodinium)


  • Gold or rust-colored dust on the body
  • Clamped fins
  • Lethargy and loss of appetite
  • Rapid gill movement

Causes: Velvet is caused by a dinoflagellate parasite that thrives in poor water conditions.


  • Raise the water temperature to around 82-84°F.
  • Dim the tank lights, as velvet parasites use light for photosynthesis.
  • Use copper-based medications as directed.
  • Maintain good water quality with regular changes and proper filtration.

4. Dropsy


  • Swollen body
  • Pinecone-like appearance of scales (scales sticking out)
  • Lethargy and loss of appetite

Causes: Dropsy is a symptom of internal bacterial infection, often related to poor water quality or kidney failure.


  • Isolate the affected fish in a hospital tank.
  • Use antibiotics designed for internal infections.
  • Improve water quality and reduce stress factors in the main tank.

5. Swim Bladder Disease


  • Difficulty swimming (floating to the top or sinking to the bottom)
  • Inability to maintain balance
  • Swollen abdomen

Causes: Swim bladder disease in bettas can result from overfeeding, constipation, or bacterial infection.


  • Fast the fish for 24-48 hours.
  • Feed a pea (blanched and shelled) to relieve constipation.
  • Maintain good water quality and consider using antibacterial medications if an infection is suspected.

6. Columnaris (Cotton Wool Disease)


  • Cotton-like patches on the mouth, fins, or body
  • Frayed fins
  • Ulcers or sores on the body

Causes: Columnaris is a bacterial infection often caused by poor water conditions and stress.


  • Isolate the infected fish.
  • Use antibacterial medications, such as those containing oxytetracycline or sulfadimidine.
  • Improve water quality and reduce stress in the main tank.

7. Popeye


  • One or both eyes bulging
  • Cloudy eyes
  • Swelling around the eyes

Causes: Popeye can be caused by bacterial infection, injury, or poor water quality.


  • Isolate the affected fish.
  • Use antibacterial medications.
  • Ensure clean, high-quality water to prevent further infections.

Preventing Diseases in Betta Fish

Preventing diseases is often easier than treating them. Here are some general tips to keep your betta fish healthy:

  • Maintain Water Quality: Perform regular water changes, use a reliable filter, and monitor water parameters such as ammonia, nitrite, nitrate, and pH levels.
  • Avoid Overcrowding: Provide adequate space for your betta and avoid overstocking the tank.
  • Feed a Balanced Diet: Offer a variety of high-quality foods, including pellets, frozen, and live foods.
  • Quarantine New Additions: Always quarantine new fish, plants, and decorations before adding them to your main tank.
  • Reduce Stress: Ensure your betta has plenty of hiding spots and avoid sudden changes in the tank environment.


Being aware of the most common diseases in betta fish and how to treat them can significantly improve the health and lifespan of your aquatic companion. Regular tank maintenance, a balanced diet, and careful observation are key to preventing illnesses and ensuring your betta thrives.


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