Axolotl Illnesses: Guide on Axolotl Columnaris and Fungus

Axolotl Columnaris and Fungus

Axolotls can be subject to different diseases introduced by bacteria or fungi such as columnaris or axolotl fungus. Being able to tell the difference between axolotl columnaris and fungus is important so you know how to treat effectively. If left untreated, columnaris can prove fatal and, in rare cases, axolotl fungus can also be deadly.

In this article, we will review the differences between these two common axolotl illnesses. By effectively telling them apart, you can give your axolotl the proper treatment. We will discuss in detail the symptoms of each disease, how to diagnose it, and treatment and prevention methods.

Axolotl Columnaris vs Fungus – What’s the Difference?

To the naked eye, axolotl columnaris and axolotl fungus look the same. However, they are two very different diseases. Axolotl columnaris is caused by a bacterial infection while axolotl fungus is the growth of the fungus known as saprolegnia. Both tend to target sick or stressed axolotls, but only axolotl columnaris will attack healthy tissue.

The only way to tell for sure which disease is affecting your axolotl is by examining the diseased cells under a microscope. Although both infections present as gray or white fuzzy growth, axolotl fungus has distinguishable branching that extends from the main body of the fungus.

Another way to tell if your axolotl has columnaris vs fungus is the location of the cottonlike growth on your pet. The saprolegnia fungus tends to originate in open wounds found on the skin. On the other hand, columnaris affects the mouth and gills of axolotl without needing to invade an open wound.

Axolotl Columnaris

Axolotl Columnaris vs Fungus

Axolotl columnaris is a bacterial infection. It typically affects stressed axolotls and presents as white or gray fuzzy growths around the gills and mouth. If left untreated, columnaris could be fatal and cause gill damage that could result in suffocation. Make sure to monitor your axolotl tank’s oxygen levels because excessive O2 can result in a columnaris outbreak.


If you suspect the axolotl has columnaris, there are a few symptoms to be on the lookout for. First of all, you will begin to see patches of gray or white fuzzy lesions growing on the gills or in the mouth of your axolotl. There does not need to be any previous injury for this bacteria to invade, but your axolotl will most likely be under stress.

Other symptoms associated with columnaris include loss of appetite and lethargic movements. If your axolotl is normally very active or a voracious eater but then suddenly stops eating or barely moves, it may be infected with columnaris.

If columnaris is allowed to spread, you may begin to notice tissue necrosis of the gills. This can lead to large portions of the organs sloughing off. Additionally, internal infections can appear as red lines extending all over the body originating from white lesions and fuzzy patches of bacterial growth.


If your axolotl starts to present symptoms of columnaris, especially the notable white patches of fuzz on the gills, you will need to confirm the diagnosis before you start treatment. Carefully remove a piece of the fungus and observe it under a microscope if possible. The bacteria should appear as long woven ropes that are slightly slimy to the touch.

If you don’t have a microscope or any definitive way to diagnose columnaris, contact your axolotl’s veterinarian. They should be able to accurately diagnose columnaris and provide you with some treatment options. If this is also not an option and you are positive that your axolotl has either columnaris or fungus, you can still begin treatment since the treatment regimens are similar for both types of infection.

Alternatively, an easy way to tell the difference between columnaris and axolotl fungus is where the patches of fuzz originate. If it is infecting healthy tissue mainly around the mouth and gills, you’re likely dealing with columnaris. Axolotl fungus does not infect healthy axolotl tissue.

Treatment and Prevention

There are several ways to treat columnaris, but early treatment is key. If columnaris is allowed to spread unchecked, it could prove fatal to your axolotl. A salt bath is one of the most common ways to completely kill off a columnaris infection.

Columnaris is caused by freshwater bacteria so subjecting your axolotl to a salt bath using seawater or a high concentration of Holtfreter’s solution for ten minutes a day for three days in a row should get rid of the problem.

Use caution when applying salt baths though because too much exposure to a high salt concentration can also make your axolotl sick. Safer methods of treatment include tea baths, antibiotic applications, adding oxidating agents like MinnFinn, or subjecting your axolotl to fridge baths.

In order to prevent columnaris from infecting your axolotl, always make sure that your tank’s parameters are optimal for your axolotl. Columnaris thrives in high oxygen environments which is also what your axolotl needs to survive. Carefully monitor your tank’s parameters including water quality. If your axolotl becomes stressed, this is an invitation for columnaris to infect healthy tissue.

Axolotl Fungus

Axolotl fungus is the result of the growth of saprolegnia from an open wound in your axolotl’s skin. The appearance of white fuzzy growth is a common symptom that saprolegnia and columnaris share and is what often get owners confused. However, one main difference is that axolotl fungus is not nearly as serious or deadly. Proper wound care and a stress-free environment are the best prevention methods for axolotl fungus.


Axolotl fungus usually only has physical symptoms as opposed to the added behavioral symptoms of the bacterial columnaris. Patches of gray or white fuzzy tufts will appear on the axolotl’s skin. These can manifest anywhere on the body where there is compromised tissue due to sickness or injury.

If left untreated, saprolegnia will kill the affected tissue. Especially those of a more delicate nature such as gill stalks and filaments. Tissue necrosis is only seen in severe cases but can have disastrous consequences for your axolotl and lead to further disease.

Your axolotl is most at risk if it is stressed out or weakened by the proximity of a sick tankmate. If you see symptoms begin to manifest shortly after noting signs of stress or behavioral changes in your axolotl, take steps to diagnose and treat your pet right away.


Axolotl fungus can be easily diagnosed with a microscope. Although, the fuzzy white patches appear similar to those caused by columnaris, upon closer inspection, the two infections are very different. Axolotl fungus has a distinguishable branching feature from the main body of the fungus.

If you look closely, you can also observe that the fungus originates within the wound of the axolotl’s skin and grows outward. By comparison, columnaris will attack healthy tissue usually around the mouth or gills. Axolotl fungus can be found anywhere on the body that has compromised tissue.

Severe cases of saprolegnia will be easily identifiable by the death of gill tissue and stalks or filaments that slough off due to massive infection of the fungus. If you are unsure if your axolotl has fungus vs columnaris, make an appointment with your veterinarian who should be able to make an informed diagnosis.

Treatment and Prevention

Saprolegnia infections can be treated in much the same way as columnaris infections. The most effective ways to treat axolotl fungus are to bathe your pet in chloramine water or an oxidating agent like MinnFinn. Do not try to remove the fungus manually since the skin and gills of your axolotl are delicate. You may accidentally do more harm than good.

If these treatments do not work, you can try salt, tea, or fridge baths. However, these can also be damaging to your axolotl, so only use these in extreme cases. If axolotl fungus has affected an entire limb of your pet, your vet may recommend amputation.

Once your pet has been cured, make sure to fully clean the tank and reintroduce your axolotl back into an optimal environment. To prevent axolotl fungus, keep water quality parameters optimal for your axolotl. This will prevent your axolotl becoming stressed or sick. Always handle your axolotl with care to avoid injury.

If you axolotl has any open wounds, treat them with an antifungal if appropriate and monitor them carefully as these are ideal places for fungus to grow.

To read the full guide on axolotl fungus, head over here White Cotton Like Fuzz On Axolotl? Axolotl Fungus – Causes And Treatment


Axolotl columnaris and fungus are similar diseases that can affect axolotls who are stressed, sick or injured. Both present as patches of white or gray fuzzy growths. However, they are distinctly different diseases.

Columnaris is caused by bacteria and will readily infect healthy tissue. It is found on the gills and in the mouth and other symptoms such as lethargy or loss of appetite can present in infected axolotls. If left untreated, columnaris can be fatal to axolotls.

Axolotl fungus, on the other hand, is caused by the fungus saprolegnia. It can be found anywhere on the body where there is an open wound. When inspected with a microscope, the fungus displays branches and tends to grow out of a wound instead of on the surface of the skin. In severe cases, amputation may be required.

Axolotl fungus and columnaris can be treated with oxidating agents. Severe cases can be treated with salt baths, fridge baths, or tea baths. In order to prevent either disease, water quality parameters should be kept optimal for axolotls since a stressed animal is vulnerable to sickness.


What Are Common Axolotl Health Problems?

Aside from bacterial and fungal infections such as columnaris and saprolegnia, the most common health problems with axolotls have to do with stress and injury.

Axolotls require certain water tank parameters in order to achieve optimal health. If their environment does not meet the conditions needed, axolotls can easily become stressed or sick. In severe cases, axolotls can become badly burned by excess chemicals in their water so always make sure to double check the appropriate environmental conditions before introducing your axolotl to its tank.

Axolotls also commonly suffer from physical injuries such as scratches, bites, and even severed limbs. While these animals are delicate and require careful handling, they are also tougher than they look. If your axolotl loses a limb, they can simply grow it back given time. However, be aware that physical injuries can become susceptible to fungal and bacterial infections.

If your axolotl begins to display an abnormal behavior or appearance, call your vet.

Why Is My Axolotl Throwing Up?

There are 4 possible causes for your axolotl throwing up such as:

  • Ammonia poisoning
  • Incorrect diet such as overfeeding or poor food quality
  • Impaction
  • Water temperature is too cold

To read more about this topic, head over here Axolotl Throwing Up? 4 Causes For Axolotl Vomit and How To Fix It!



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.

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