Axolotl care

18 Axolotl Diseases: Identification, Causes & Treatment

18 Axolotl Diseases: Identification, Causes & Treatment

"What's wrong with my axolotl?" you may ask.

"It's not acting right. Is it sick? Does it have a disease?"

It's entirely possible.

But before we get started, a quick disclaimer:

Many axolotl "diseases" are actually not true diseases at all, but a result of poor conditions in its aquarium.

Whenever you suspect your axie isn't doing well, a really good idea is to perform a water test.

The full range of parameters - ammonia, nitrite, nitrate, pH, KH & GH are what you want to know.

Now that that's out of the way...

... Let's look at these 17 illnesses that can affect our axies.

I have organized them by category (bacterial, parasitic, fungal, environmental and other).

Without further ado - let's dive in!

Bacterial Diseases

Bacterial diseases are some of the most common illnesses that affect our axolotl buddies.

They can also be very deadly.

The good news is if caught early enough and given the proper treatment, the animal should usually recover. :)

1. Columnaris

Those who are familiar with keeping guppies may recognize that word.

What's columnaris?

To the naked eye, it may appear to be identical to fungus, but it is actually a bacteria.

(Under the microscope, it looks much different.)

Though left untreated it can kill the animal, columnaris is quite treatable if caught soon enough.


  • Fluffy gray or white patches
  • Lethargy
  • Loss of appetite

Causes & Prevention:

Stress can bring on columnaris infection, which is opportunistic in nature.

"Opportunistic" means it is always lurking around, ready to strike.

If the animal has recently been moved or is older or weak, that can prompt a columnaris attack.

Minimizing stress through ensuring proper environmental conditions is the best way to prevent it, as well as quarantining new inhabitants.


There are a wide variety of treatments for this condition.

Antibiotics and salt baths can be useful for fighting columnaris, though I personally try to avoid these.

With Columnaris, it can be a bit tricky because unless you have access to a microscope, you don't want to accidentally treat for columnaris only if it is actually fungus.

So I like to choose a treatment that can knock out BOTH.

If I suspect Columnaris, my go-to is MinnFinn.

That is so great because it treats both.

2. Septicemia

Septicemia occurs when various types of harmful bacteria invade the axolotl's body, resulting in the poisoning of the animal's bloodstream.

The kinds of bacteria that can cause this condition include aeromonas and pseudomonas.

Ever heard of "red leg" disease?

The bacteria that cause that are aeromonas (specifically, aeromonas hydrophilia{2}).

Red leg is a condition that commonly affects African dwarf frogs, but axolotls can get it as well.

When the bacteria that cause septicemia penetrate a vital organ, the animal does not have long to live. :(


These are the symptoms of septicemia in axolotls (note that an axolotl affected with this disease may not show all of them, depending on the nature of the infection):

  • Loss of appetite
  • Abdominal bloating
  • Redness & swelling of limbs (in the case of red leg)
  • Ulcers/body sores
  • Weight loss
  • Internal bleeding/hemorrhaging (results in red or bruised looking areas)
  • Changes in neurological function that result in seizure-like movements (in advanced stages)

Causes & Prevention:

As with columnaris, bacteria that cause septicemia are always present in the aquarium{1}.

It rears its ugly head when the animal is weakened by stress or other factors.

The best way to stop an outbreak is to keep the animal's immune system strong through proper environmental conditions and nutrition.

Quarantining new inhabitants is also highly recommended.


Here's the thing:

As with many diseases but especially in the case of septicemia infection, to be effective, treatment should be given as soon as possible. The longer you wait, the smaller the chances grow of reversing the condition.

Time is of the essence here!

Medications that tend to prove most effective are those that are administered internally, where the infection is, rather than those that are dosed in the water column.

A veterinarian will usually prescribe injections of antibiotics.

If a vet is not available, you can try treating with water-borne antibiotics such as Furan 2 (Nitrofurazone), EM Erythromycin or Kanaplex (kanamycin).

Please note that it is also recommended to isolate the affected animal to help curb the spread of transmission to the other aquarium inhabitants, as this disease is contagious.


If this therapy is started in time, the animal often has a good shot at recovery, unless the bacteria that have caused the symptoms are not in fact aeromonas/pseudomonas, but rather...

3. Mycobacteriosis

Mycobacteriosis is prevalent in fish aquariums, but it can affect axolotls as well.

It is also known as fish granuloma or fish TB.

This disease causes small round granulomas to occur in the tissues of the animal, which are actually the animal's way of trying to isolate and fight the infection.

In a necropsy, visible white granuloma nodules may often be seen inside the body cavity and on the internal organs of the animal.


As with septicemia, the symptoms that show up can depend on the site of infection.

  • Wasting (if the infection is in the digestive system)
  • Bloating
  • Changes in neurological function
  • Loss of appetite
  • Red sores/ulcers

Did you notice how the symptoms mirror those of septicemia?

That's what makes them so hard to tell apart.

To the naked eye they appear clinically the same.

It takes special lab diagnostics to confirm with 100% certainty that an axolotl is indeed affected with mycobacterosis.

Causes & Prevention:

This condition is more common in older or weaker animals or animals that have been severely stressed.

My personal opinion is that it is more risky to acquire axolotls from pet stores


If an axolotl has been given early treatment for what appears to be septicemia and does not respond, this may lead one to suspect the underlying condition was actually mycobacterium.

Unfortunately, there are no known treatments for this condition in axolotls, only preventative measures{2}.

This is because by the time you start seeing symptoms, it means the immune system is already on the losing end - the immune system which is the biggest weapon the axie has against disease.

There are things you can do to try to build the immune system back up.

These things include:

  • Feeding a nutritious diet
  • Keeping the temperatures optimal
  • Minimizing stress
  • Treatments of Vitamin C

That said...

... In the case of a sick axolotl suffering from mycobacterial infection, such measures are usually just a temporary boost that only helps for a while only for the symptoms to come back later on, because the bacteria are still in the animal's system.

So I don't want to create false hope, but some owners feel it is worth a try.


If you have a diagnosis of myco on your hands, it is important that you are aware this disease can be transmittable to people.

Those who are immunocompromised, elderly or have open wounds on their hands when they clean the tank are most vulnerable (hence why it is a good precautionary measure to wear aquarium safe gloves when interacting or servicing the tank).


Based on the information above many owners decide that it is best to euthanize the afflicted animal.

Related Post: Axolotl Safe Medicines & Treatments

Fungal Diseases

As many axolotls know, fungus is one of the most common diseases to affect axolotls.

This species is prone to attacks by fungus, called saprolegnia, which can lead to tissue damage.

4. Saprolegnia (Fungus)

Saprolegnia is the technical name for fungus that often affects our axolotl friends.

Because it loves cold water, it frequently shows up in axolotl tanks.


Affected animals may show the following clinical signs:

  • Fluffy white cottony tufts on the axolotls gills, limbs, head or body
  • White or gray patchy areas
  • Tissue necrosis (especially on the gill filaments and stalks)

Causes & Prevention:

Saprolegnia likes to attack when the animal is stressed or weakened.

This can be due to dirty living conditions, improper water temperature or injury from a tankmate.

Maintaining the tank at the proper temperature along with regular maintenance and preventing aggression are the best ways to prevent saprolegnia fungal infections from occurring.


Because to the eye it can appear the same as columnaris, a treatment that targets both conditions is recommended.

If the infection is very severe, amputation of the affected limb may be advised by a vet.

Read more about fungus and its treatment here.

Parasitic Diseases

There are a variety of parasites that can affect axolotls.

Parasites can come from a fish tank at a pet store where the axolotl was housed with a central filtration system, or be introduced by other aquatic species added to the tank for food or ornamental purposes.

Their effects on the health of our animals can be profound.

But the good news is MOST of them are treatable and are not as virulent as the bacterial infections detailed in earlier sections.

And unlike many bacterial infections, parasites are always introduced.

This means they are much easier to control via proper quarantining procedures.

5. Intestinal Nematodes

These are possibly one of the most common diseases found in axolotls.


There are many symptoms of intestinal nematodes in axolotls, but some of the most common are:

  • Vomiting worms
  • Weight loss
  • Gill degeneration
  • Bloat

Causes & Prevention:

This disease is transmitted from an infected axolotl to an infected axolotl, or from a live food source or water/equipment contaminated with this disease.

Prevention is done through proper quarantine protocols and possible prophylactic treatments.


There are several treatment options for this disease, depending on how advanced the infection is, but it is usually either through food or water-borne treatment.

Learn more about intestinal worms in axolotls here.

6. Hexamita

It takes a microscope analysis of the fecal matter of the animal to observe this parasite, as internal hexamita is located in the intestines of the axolotl.

But the owner may be suspicious of hexamita when they observe the following...


Intestinal parasites such as hexamita can cause an axolotl to chronically struggle with maintaining a healthy weight.

No matter how much the animal eats, it continues to remain skinny.

The animal may also have inappetence.

It is probably safe to say that hexamita is relatively uncommon in axolotls.

Causes & Prevention

Hexamita is thought to be transmitted by feeding live foods to the animal that are infected with this disease, such as bait fish.


These pesky protozoans can be treated with Metronidazole (also known as Flagyl), added to the food.

7. Opalina

There are conflicting trains of thought on opalina.

One is that these creatures are not harmful to the amphibians they inhabit.

The other is that there are over 200 species of them, and some evidence may suggest some of them may be parasitic in nature and function similarly to hexamita.

They also appear to multiply inside the host, which is characteristic of a parasite.

It is thought that congestion of the parasite in the axolotl's digestive tract may lead to mortality.


Not much is known on the symptoms of opalina in axolotls. Symptoms are presumed to be the same as hexamita.

It is probably safe to say this disease is relatively uncommon in axolotls.

Causes & Prevention:

As with hexamita, avoid feeding untrusted live foods.


Treatment is the same for opalina as it is for hexamita. See hexamita above.

8. Trichodina

Trichodina is a parasite that is invisible to the naked eye, but under the microscope appears as a circular shaped, rotating organism with a fine ring of cilia around its perimeter. It uses these cilia to grab onto the host and move around, causing irritation to the skin and gills.

Quarantining of the affected animal is unnecessary as all of the aquarium will be infested.


The irritation the parasite causes leads to excess slime production for the axolotl.

Causes & Prevention:

Trichodina is introduced via contaminated fish, plants or aquarium water.

It is prevalent in dirty water with high organic loads, especially in outdoor ponds where the water quality has deteriorated, leading to an abundance of bacteria on which the parasite feeds.

Quarantining new inhabitants, as well as properly managing organic matter that accumulates in a system is the best mode of prevention.


Treatment with formalin baths are sometimes employed to treat trichodina.

For axolotls, MinnFinn is particularly effective at eradicating this disease.

The combination of the two active ingredients (hydrogen peroxide and peracetic acid) in this medicine as a short-term bath administered every other day for several treatments proves to be a powerful treatment that kills these parasites.

9. Costia

Costia is an incredibly tiny parasite that appears under the microscope as a tiny twirling, comma shaped organism.

It is known for being one of the fastest killing parasites, as it can multiply incredibly rapidly, leading to mortality if not addressed in time.

A highly contagious disease, all animals exposed to the infected one will need to be treated.


As with Trichodina, excess slime production is an indication of a costia infestation.

Causes & Prevention:

Costia can infest your aquarium through the introduction of fish that have not been properly quarantined, or other contaminated sources such as water from the pet store or aquarium plants.

Preventing costia is much easier than trying to treat it, so please quarantine all new fish thoroughly and don't add water from a pet store into your tank ever.


MinnFinn can be used to treat Costia infestations. The oxidizing effect of the treatment is lethal to these parasites.

10. Myxobolus Cerebralis

Also known as "whirling disease," this is a very scary illness in which the parasite begins tampering with the functions of the animal's brain, resulting in a loss of equilibrium.

Thankfully this is not a very common disease in axolotls (or transmissible to people).

However, myxobolus is known to affect them.

As the disease progresses, the animal often develops debilitating skeletal deformities from the unnatural swimming positions it assumes, and ultimately starves due to inability to eat properly.

The disease is highly contagious, but affected fish should be isolated to try to halt the spread of the infestation.


  • Swimming in circles
  • Inability to eat
  • Floating sideways or head down
  • Bent spine
  • Emaciation

Causes & Prevention:

Some species of worms are connected to the transmission of myxobolus.

While earthworms are generally considered safe, tubifex worms should never be fed to an axolotl as they are thought to be the primary vector for transmission.

This disease is more likely to affect animals kept outdoors due to contaminants entering the pond.


Sadly, myxobolus almost always proves fatal to the affected animal and euthanasia is most often recommended. That said, in a few rare cases treatment has been successful using a combination of several antibiotics (Kanamycin, Nitrofurazone and Metronidazole). The owner will need to make their best decision.

Environmental Diseases

Though not technically "diseases" in the sense of a known pathogen causing the illness, the following conditions can result in detriment to the axolotl's health.

As stated in the preface, it is worth noting that symptoms caused by environmental issues can appear identical to those in some of the diseases described earlier.

That's why it's a good idea to start with examining the conditions the axolotl is living in prior to assuming the animal has an actual disease.

11. Overheating

As you are probably aware, axolotls are cold-water animals that actually display signs of illness when exposed to temperatures that are outside of their comfort zone (generally considered to be 60-64F).

They are native to a lake fed by glacial waters, and exposing them to higher temperatures can prove harmful or even fatal.


  • Loss of appetite
  • Floating issues
  • Fungal infections
  • Bloating

Causes & Prevention:

If you live in an area where the temperatures become too warm for the axolotl's aquarium, it is a good idea to invest in an aquarium fan or chiller to help keep the temperature within the appropriate range.


An axolotl suffering from overheating can be placed in the refrigerator as an emergency measure.

Treatment to prevent secondary infection (such as Holtfreter's solution) is a recommended course of action.

12. New Tank Syndrome

New tank syndrome results in an aquarium with high ammonia or nitrite levels.

Exposure to ammonia and nitrite can result in burns that damage the axolotls skin and gill tissue.

A water test should be performed immediately if you suspect new tank syndrome.


  • Loss of appetite
  • Shrinking gill filaments
  • Redness of the skin
  • Lethargy
  • Changes in neurological function

Causes & Prevention:

Axolotls can suffer from new tank syndrome when they are left in a new aquarium without a cycled filter or enough water changes to combat rising ammonia.

Another scenario that can result in new tank syndrome is the use of chemicals or medications that destroy the beneficial bacteria in the aquarium's filter.

Still another cause can be overfeeding or overstocking.


Clean water is the best treatment for this problem.

Reducing the ammonia and nitrite by performing large water changes is advised, as well as reducing feeding and stocking densities (if applicable).

Adding ammonia binding treatments may be advisable.

13. Old Tank Syndrome

While many hobbyists are aware of new tank syndrome, one problem that is not as well known is old tank syndrome.

When in doubt if the axolotl is suffering from old tank syndrome, please test the water immediately.


  • Bulging eyes
  • Cloudy eyes
  • Inappetence
  • Excess slime production
  • Lethargy
  • Floating
  • Bloating

Causes & Prevention:

Over time, biological processes result in the creation of acid.

Without counteractive measures, this acid brings down the pH of the aquarium, also known as a pH crash.

This gradual acidifying of the aquarium can be prevented through regular water changes or adding proper buffering agents to the filter.

Another result of old tank syndrome is high nitrate levels.

Evaluating the aquarium's maintenance schedule is a good place to start, to ensure nitrate and pH levels are kept within their proper ranges.


In the case of high nitrates, small frequent water changes are advised to gradually reduce the levels of nitrate (too much too quickly could cause shock from the large change in nitrate levels).

In the case of a pH crash, it is advisable to bring the pH back up to normal as fast as possible by performing large water changes.

Other Diseases

14. Tumors

While axolotls are highly resistant to cancer, they do occasionally get benign tumors.

These growths do not usually interfere with the animal's wellbeing, though a veterinarian can often remove them if it is advisable.

15. Organ Failure

Whether organ failure in lotls occurs as the result of genetic predisposition, diet or disease is not always understood, though these three may all play their part.

When it happens, the axolotl may go off its feed, bloat and sometimes develop bruised looking patches on its stomach or cloaca.

Organ failure is not treatable, and euthanasia is recommended.

16. Impaction

Axolotls will often attempt to eat large hard objects, such as pebbles, marbles or snails - anything that fits in their mouth.

While many times they are either able to regurgitate the object or pass it through...

... Sometimes they end up swallowing something that is too difficult for them to pass.

In that case, a vet may be needed to surgically remove the foreign object from their stomach.

You may suspect impaction if the animal looks wider than normal when viewed from above, loses interest in food or is vomiting.

Impaction via constipation can also cause your axolotl to become sick.

A constipated axolotl may float and stop eating.

Refrigerating the axolotl can help encourage the animal to pass the obstruction, whether it is air or food.

17. Injury

Axolotls can suffer injury from mechanical filters, bites from tankmates, or other accidents.

Good news:

Though this can be worrisome, axolotls have remarkable abilities to regenerate nearly every part of their body, including parts of their brain, heart, entire limbs, gills and more.

For an injured axolotl, the recommendation is to try to keep the wound from becoming infected by either fungus or bacteria.

Placing the animal in water treated with an antiseptic solution, salt or tea baths and keeping the water clean is advisable.

For severe trauma or if you suspect the wound is becoming infected, a veterinarian's advice should be consulted.

18. Stress

Axolotls can become stressed for a number of reasons.

We should try to avoid stress in our animals as much as we can, as it weakens their immune system, predisposing them to disease.

A stressed axolotl may:

  • Stop eating
  • Vomit
  • Hide
  • Swim wildly

Though sometimes stress is inevitable, there are things we can do to try to help calm the animal down.

Measures such as reduced light, provide access to hides, good water quality, avoiding disturbing the animal through physical contact, separating aggressive tank mates and providing proper nutrition can greatly help the animal to normalize faster.






Reading next

How to Tub an Axolotl: 5 Steps + Tubbing Benefits

Leave a comment

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.