Columnaris, also known as Cotton Wool Disease or Mouth Fungus, is a bacterial infection that can affect Betta fish and other freshwater fish species. It manifests as white, cottony patches or lesions on the fish’s body, fins, and mouth. Treating Columnaris requires prompt action to prevent the infection from spreading and causing further harm to the fish. Here is some general information on how Columnaris is treated:

• Check Water Parameters:
  • Test the water parameters (ammonia, nitrite, nitrate, and pH) in the main tank and/or quarantine tank. Poor water quality can stress the fish and exacerbate fin rot. Perform a partial water change if necessary to improve water conditions.
• Maintain Water Quality:
  • Ensure the water in the quarantine tank is clean and free from any harmful substances. Perform regular partial water changes as needed to ensure the parameters are in check.
• Maintain optimal water temperature:
  • Bettas are tropical fish and require a water temperature between 78°F to 80°F (25°C to 27°C). When changing water ensure the new water is the same temperature to avoid shock. Use a reliable aquarium heater and thermometer to maintain a stable temperature in the tank.

• Isolate the Betta (Optional):
  • If you have a separate quarantine tank, isolate the affected Betta fish to prevent the spread of the infection to other tank mates.

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• Common medications used:
  • Columnaris is a bacterial infection, and treating it with antibiotics is usually necessary. Look for medications specifically designed to treat bacterial infections in fish.
  • Some effective antibiotics for Columnaris treatment include Kanamycin, Doxycycline, Minocycline, or Erythromycin. Follow the manufacturer’s instructions for dosage and application carefully.

• Supportive Care:
  • Keep the Betta’s environment calm and stress-free. Provide hiding spots, dim lighting, and maintain the water temperature within the recommended range (78-80°F or 25-27°C).
  • Offer a varied and balanced diet of high-quality pellets, flakes, and occasional treats like frozen or live foods to support the fish’s immune system and overall health.
• Remove Organic Debris:
  • Remove any organic debris, uneaten food, and dead plant matter from the tank. A clean environment can support the fish’s healing process.
• Maintain the Treatment:
  • Continue the antibiotic treatment for the full recommended duration, even if the visible signs of the infection improve. This ensures that all bacteria are eradicated and reduces the risk of a relapse.
• Monitor Behavior and Symptoms:
  • Observe your Betta’s behavior and look for any specific symptoms or changes in its appearance. Note any improvement or worsening of the infection.
• Consult a Veterinarian:
  • If the Betta’s condition worsens, or if you are unsure about the diagnosis or treatment, it’s crucial to consult a qualified veterinarian experienced in fish health.
  • A veterinarian can conduct a proper examination, identify the disease, and provide appropriate treatment options.

Remember that Columnaris can progress rapidly and have severe consequences if left untreated. Timely intervention and appropriate care are essential for your Betta fish’s recovery and overall well-being. It’s always best to seek professional veterinary advice if you are unsure about how to proceed with the treatment.