Axolotl Fungus: How to Identify & Treat It

Fungal infections are one of the most common health issues in axolotls. The good news: caught early, they are very treatable.

Identifying Fungus

Fungus on axolotls appears as white, fluffy, cotton-like growths. Common locations:

• Gills: most common site, appears on gill filaments
• Limbs: especially on toes or areas with recent injuries
• Tail tip: particularly after nipping from tank mates
• Body: less common, usually indicates advanced infection

Do not confuse with:

• Normal slime coat (smooth, not fuzzy)
• Shed skin (thin, transparent sheets)
• Bacterial infection (smooth white patches, not fluffy)

Causes

• Poor water quality: the #1 cause. High ammonia or nitrite damages the slime coat, allowing fungal spores to take hold
• Injury: any wound is vulnerable to fungal colonization
• Stress: chronic stress weakens the immune system
• Cold temperatures: while axolotls need cool water, very cold temps (below 10°C) can reduce immune function

Treatment

Step 1: Improve Water Quality (Always)

Test water immediately. If ammonia or nitrite is above 0 ppm, do a 50-80% water change. This alone may resolve mild cases.

Step 2: Salt Baths

For active fungal growths:

1. Prepare a container with 1 liter of dechlorinated tank water
2. Add 2-3 teaspoons of non-iodized salt (aquarium salt or pure sea salt)
3. Dissolve completely
4. Place the axolotl in the salt bath for 10-15 minutes
5. Return to the main tank
6. Repeat daily for 5-7 days

Never add salt directly to the main tank. Axolotls are freshwater animals and prolonged salt exposure is harmful.

Step 3: Methylene Blue (Severe Cases)

If salt baths do not resolve the infection after 5-7 days:

1. Prepare a separate container with dechlorinated water
2. Add methylene blue according to product instructions (usually 1-2 drops per liter)
3. Soak the axolotl for 30 minutes
4. Repeat daily for 3-5 days

Step 4: Fridging (Last Resort)

For severe, unresponsive infections, fridging at 4-8°C slows fungal growth while boosting the axolotl’s immune response.

Prevention

• Maintain optimal water parameters at all times
• Perform weekly 20-30% water changes
• Remove uneaten food promptly
• Avoid injuring axolotls during handling or tank maintenance
• Quarantine new axolotls for 2-4 weeks before adding to an existing tank