White Cotton Like Fuzz On Axolotl? Axolotl Fungus – Causes And Treatment

White Cotton Like Fuzz On Axolotl

Axolotls are fragile animals and can develop a variety of health problems. One of these health problems presents in the form of white cotton like fuzz growth on axolotl, also known as axolotl fungus. The good news is that axolotl fungus is treatable and even better – it’s preventable.

This article will help you establish if your axolotl is suffering from fungus, how to treat it and how to prevent future re-infections.

Axolotl Fungus – What Is It?

Axolotl fungus is the white cotton like fuzz that appears on your axolotl’s body and gills. Normally, the fungus develops in stressed axolotls or starts growing from open wounds. Furthermore, this bacteria thrives in cooler water which also happens to be the type of water axolotls need to be kept in. This makes the axolotl susceptible to fungus and that is why they are often seen being affected by it.

There are two types of bacteria that are associated with axolotl fungus – columnaris and saprolegnia.


Columnaris is a gram-negative, aerobic, bacteria that thrives in fresh water. This bacteria can survive for a whole month in clean, well-oxygenated aquariums. That’s why axolotls often suffer from this disease.

However, it’s important to note that the bacteria will not infect a healthy animal. The axolotls that are most at risk are either young, old, or stressed. As axolotls are very easily stressed by even the slightest drop in water quality such as temperature changes, ammonia/nitrate spike, etc, this makes them the perfect candidate for axolotl fungus.

Although, treatable, if ignored fungus can quickly result in death. Therefore, it’s essential to act at the first sight of symptoms.


The other possibility for the white cotton like fuzz on axolotl is the bacteria – Saprolegnia. This is the most common fungus amongst aquatic pets.

One major difference between Columnaris and Saprolegnia is that the latter doesn’t affect the health tissue! Normally, Saprolegnia will attack either dead/dying organic matter such as an open wound on your axolotl or a stressed/sick axolotl.

Axolotl Fungus – Cause

axolotl fungus

The main cause for the white cotton like fuzz fungus is your axolotl’s immune system being weakened due to being stressed. Possible stressors include poor water conditions or an open wound.

The poor water conditions that can cause stress to your axolotl include:

  • Lack of water cycling
  • Build-up of feces or waste. An unbalanced environment with too much dissolved organics may lead to outbreaks of fungus
  • Warmer water temperatures that can result in ammonia/nitrate spike in the tank
  • Lack of strong microbiome. Most common with tanks that have a bare bottom or sand only
  • Contamination of the enclosure with disinfectants, soaps, or detergents

To summarise, poor water quality or incorrect water parameters can result in your axolotl’s immune system weakening and/or open wounds. This will then subsequently lead to the white cotton fuzz like growth on axolotl, also known as fungus infection.

In some rare cases, an axolotl can develop fungus and all the conditions might appear up to standard. Even in these cases, the cause is still some kind of stress or something being off in their environment. It’s essential to find out what that is and treat the root cause to avoid reinfection.

Axolotl Fungus – Diagnosis and Symptoms

white cotton like fuzz on axolotl

As already discussed, the white cotton like fuzz on axolotl can be one of the two axolotl fungus bacteria – columnaris or saprolegnia. Being able to tell the difference can help you use the correct treatment and get the best results. So, how to tell the difference?

The only certain way to know is by looking at the bacteria under a microscope. However, there are some characteristics that you can keep an eye out for that would help you determine what type of white cotton like fuzz on axolotl you’re dealing with.

Although, some of the axolotl fungus symptoms will be the same such as scratching the irritated areas, there are also differences that can help you determine which bacteria has infected your axolotl. Let’s take a look!


If you are inspecting the white cotton like fuzz under the microscope and see long “branches” protruding from the body, it’s saprolegnia.

However, if you don’t have a microscope laying around, keep an eye out for the following saprolegnia characteristics:

  • White or grey in color
  • The white cotton fuzz like growth on axolotl appears as hairy, patchy film or tufts of hair on the skin
  • Saprolegnia looks like dandelion fluff (unlike Columnaris)
  • It grows upwards and out of an open wound
  • It’s found on the skin instead of on the gills
  • Axolotl scratching like a dog the infected fungus area


The other possibility, for the white cotton like fuzz on your axolotl, is the columnaris bacteria. Although, it has fungus like appearance, the columnaris is not exactly an axolotl fungus.

To determine if it’s the columnaris type of axolotl fungus you’re dealing with, check for the following characteristics:

  • Grows on the gills or mouth
  • If the growth is on the gills, it can result in cloudy tips and degeneration of the gill filaments, which is tissue necrosis
  • Thrives in O2 rich environments
  • The color of this type of axolotl fungus ranges from translucent white to an opaque off-white color
  • The shape of the growth consists of long stands of “fiber” woven together, similar to a cotton ball or tangle of sting. It’s less fluffy but slimier and stringier appearance
  • If the infection has spread to the axolotl’s internal organs, it will appear on the outside as red streaking all over the axolotl’s body
  • If your axolotl’s lesions or sores are completely red instead of white, it’s not columnaris
  • Axolotl scratching like a dog the infected fungus area

Understanding the difference between the two types of bacteria will help you decide on the best course of treatment. Let’s take a look at what are the treatment options.

Axolotl Fungus – Treatments

white cotton fuzz like on axolotl

Although, in most cases treatable, if left untreated, axolotl fungus can quickly result in death if ignored. The other unfortunate thing that can result from not treating axolotl fungus is full deterioration of the frills on your axolotl’s gills, leaving them with nothing but bare stalks.

Before looking at the types of treatment, it’s important to note two things:

  • You should never try to pull the fungus off the axolotl manually. Even if you pull the fungus off, it will 100% come back. Not only is it ineffective and pointless, but it would also be extremely stressful and painful for your axolotl as the gills are so sensitive
  • Whichever treatment you choose, you should be prepared that it can take up to 2 weeks for the axolotl fungus to resolve and that’s if your first choice of treatment even works

Now, let’s take a look how to treat the different types of axolotl fungus bacteria.


If the white cotton like fuzz on axolotl is the Columnaris bacteria, follow these steps to treat it:

  1. Remove the sick axolotl and any other axolotls from the tank
  2. Place the axolotl in a hospital tub
  3. Treat the tank water with Seachem Prime followed by 100% water change every 24 hours (use below link to purchase)
  4. Before placing the axolotl back in the tank, test the water perimeters as that’s essential for their recovery (use the link below to purchase water testing kit). Maintain the temperature at the lower end of the spectrum as Columnaris typically does not survive in temperatures below 53°F
  5. During this process, feed them only nutritious food such as earthworm or pellet

Other treatments include:

  • Tea baths. The acids will create a hostile environment for Columnaris to grow in. Head over here for the axolotl tea bath guide Step By Step – Axolotl Tea Bath, Salt Bath, Antibiotics
  • Fridging. This involves setting your fridge at temperature between the ranges of 41°F to 46°F. Then, placing your axolotl in a tub with dechlorinated water. Place a lid on it. Leave it in the fridge and check daily to perform water changes and to feed the axolotl. Leave in the fridge for up to 2 weeks
  • MinnFinn is an oxidizing agent. It can be used at regular strength for the 1 hour bath and repeat 1 to 3 times, depending on the severity of the case. However, in harder water, it doesn’t work as well at regular strength or in water that has been treated with Prime. It can take anything from 2 days to 2 weeks for this treatment to work depending on the severity of the fungal infection

Columnaris – Severe Cases

If the treatment for Columnaris isn’t started at the cotton-growth stage, it can result in lesions on gill tissue or the surrounding skin to the point when the gills stop functioning properly. Furthermore, it can enter the blood and cause systematic infection.

If Columnaris start infecting the organs, it can result in kidney failure which subsequently can lead to water and waste buildup. This will make the axolotl appear bloated. If your observing all of the mentioned symptoms, it means you’re dealing with a sever case.

In severe cases, try one of the following more aggressive approaches (don’t apply all of these at once, pick one and test it for 1-2 weeks):

  • Baths of methylene blue at half dosage
  • Antifungal antibiotics like itraconazole or Furan 2 is at half dosages
  • Salt baths should only be attempted when the infection keeps coming back and is systematic. Salt baths is like chemotherapy. It’s an aggressive and last resort type of approach

Most of the time, getting the water perimeters right and lowering the water temperature should strengthen your axolotl’s immune system and they should be able to fight off the infection on their own.

If the water is the right perimeters and you’ve tried everything listed above, including the more aggressive treatment such as the itraconazole, then the prognosis isn’t great.

For the step by step guide on how to do salt baths or administer antibiotic treatment, head over here Step By Step – Axolotl Tea Bath, Salt Bath, Antibiotics


Similar to Columnaris, the Saprolegnia axolotl fungus is also treated by:

  1. Removing the axolotl from the tank
  2. Cycling the water
  3. Ensuring you have the correct water tank perimeters
  4. Once the axolotl is back in the tank, you can add tannins to the water and keep the temperature on the lower end of the spectrum for a few weeks

Other treatments that can be used include the oxidizing agent MinnFinn, fridging and tea baths. In severe cases and only as last resort – anti-fungal antibiotics or salt baths.

Axolotl Fungus – Prevention

As with most other diseases, preventing axolotl fungus is much easier than having to treat it. Not only that but once recovered from it, axolotl fungus can easily come back if the root cause hasn’t been addresses or new stress factors are affecting your axolotl. Therefore, the prevention tools are key to keeping the fungus at bay.

As already discussed, the main cause for axolotl fungus is your pet being stressed. So, what stresses axolotls? Often that’s the incorrect tank perimeters and poor water quality such as water temperature, incorrect pH, ammonia/nitrate spike, etc.

The main factors to focus on are environment and water quality.


Often axolotl fungus is the result of an environment that lacks eco balance such as a bare bottom tank or tanks with sand only.

To prevent axolotl fungus, consider a more natural approach to your axolotl tank that provides a strong colony of good tank flora. This would help to diminish bad organisms that can cause fungus.

One example of that is a planted tank with a Walstad-style substrate.

Water Quality

The other important factor in preventing axolotl fungus is water quality. This includes the following:

  • Regular water changes, also known as cycling your tank. This keeps the dissolved organic levels in the water to a minimum. If the water is not cycled properly, organic material such as uneaten rotting food, can result in axolotl fungus infection
  • Water temperature should be at 59°F to 65°F and maintained the same without any sudden changes as that can stress your axolotl
  • Ammonia levels should be 0
  • pH levels. The ideal pH is 7.4-7.6
  • Nitrite levels should be 0
  • Chlorine is harmful for axolotls. Therefore, the water in their tank must be either dechlorinated or left to stand for 24 hours before adding it
  • Water hardness. Axolotls prefer water that is slightly hard. This means that they need a good concentration of dissolved salts in their water. Hard water ensures healthy gills and healthy slime coat production

Final Thoughts

If you’re dealing with axolotl fungus, the good news is that is treatable as long as you act quickly at the first sight of symptoms. With that said, the symptoms of axolotl fungus to keep an eye out include gills deteriorating, white cotton like fuzz on axolotl.

For your axolotl to have developed fungus, they must have been stressed in the first place, so look out for symptom of stress such as curled gills, curled tail tip, frequent gulps of air, floating, frantically swimming or an open wound where the fungus could have started growing.

There are two types of axolotl fungus bacteria – columnaris and saprolegnia. The treatment for both bacteria is similar – determining the cause of your axolotl’s stress, removing the axolotl from the tank, performing water changes, treating the water whilst feeding them a nutritious diet.

By providing the right conditions, your axolotl’s immune system should be able to fight off the infection on their own.

In really severe cases, antibiotics or salt baths can be used. Whatever treatment you decide to go with, it would take 1 to 2 weeks for your axolotl to recover from fungus infection.

If nothing works, you should take your pet to a specialised vet for further advice and treatment.

Frequently Asked Questions/FQA

Why Is My Axolotl Itchy?

Axolotls scratching and being itchy can be a sign of a health problem such as poor water conditions (warm water temperature, ammonia/nitrate spike, etc) or injury/fungal infection.

To read the full guide on itchy axolotl, head over here Itchy Axolotl? Why Is Your Axolotl Scratching And How To Stop It

Why Are My Axolotl Veins Showing?

Axolotl’s veins can be visible for normal reason such as increased activity such as swimming or just eating. On the other hand, it can be a sign of a health problem such as poor water conditions, impaction, injury, or stress from something else.

Head over here to read the full guide on axolotl veins showing Axolotl Veins Showing? What Does It Mean and When To Worry?




My name is Iliyana and I'm a passionate animal lover and pet owner. As there is significantly less information online about unusual and exotic pets, I decided to found this website and recruit expert writers to help pet owners.

You may also like...