Axolotl ammonia poisoning

5 Reasons Why Your Axolotl May Have Died

5 Reasons Why Your Axolotl May Have Died

It's always so sad - and sometimes quite frustrating - when your axolotl perishes.

Possibly the hardest part...?

Sometimes it can be difficult to know what went wrong.

So today I've put together a list of the top reasons an axolotl might die.

With a bit of detective work, hopefully you are able to pinpoint the cause and feel better about the situation - maybe even using that knowledge to improve going forward.

Let's get to it.

1. Bacterial Infection

I've talked about this in another post, but with axolotls, I believe the biggest killer is pathogenic bacteria.

What does it look like?

The symptoms can vary widely.

Sometimes an axolotl may swell up and die fairly quickly, or perish almost overnight with no other explanation.

Other times, the animal languishes away for months from a seemingly mysterious sickness that starts out with small issues, such as simply a loss of appetite. 

There are many types of bacteria that can cause disease in axolotls, and many of them are present in every aquarium.

The bad news is, bacterial infections are far too common in the axolotl world.

The good news is in many cases bacterial infection can be prevented.

2. Poor Water Quality

This is a big one.

On the bright side, most axolotl owners are aware of the importance of monitoring their water quality and ensuring their parameters are where they should be.

But water quality can be sneaky, and sometimes things can seem to be going well for a while, lulling us into a false sense of security.

Things can suddenly turn when, for example, the pH crashes unexpectedly ("old tank syndrome") or medications wipe out the filter.

When that happens, it can spell trouble or even death for the axolotl.


It is a good idea to test the water daily for tanks that have been newly set up with an axolotl for the first month, and then on a weekly basis for more established systems.

That way it is easier to spot a small issue with water quality before it becomes a big one and get it corrected in time.

Sometimes the water may look perfectly clear and the axolotl seem healthy, but meanwhile the nitrites are creeping up to unacceptable levels as a result of insufficient filtration or a newer tank.

3. Jumping Out

Axolotls are jumpers, and they can perform these acrobatics when you least expect it to happen.

That's why we recommend making sure not to fill the water above at least 3" of space to the top of the tank, or keeping a secure lid on the aquarium at all times.

When an axolotl jumps out, they can suffer from injury, and if they are left out too long, they will lose too much moisture.

It can be hard to revive an axolotl that has gotten to dry.

Once an axolotl has escaped, it may also crawl a considerable distance before it is finally found, at which point it might be too late to help it.

4. Oxygen deprivation (hypoxia)

Axolotls are extremely efficient creatures when it comes to uptaking oxygen from their environment. 

Despite that, they still have their limits.

If conditions become too extreme, they can suffer from hypoxia, leading to coma and eventually death.

Fortunately this is rare in the average home aquarium with a working filter, and tends to be more of an issue when axolotls are being transported from place to place.


Live plants are another great way to boost oxygen levels.

5. Transmitted Disease

In many cases, axolotl owners have purchased "feeder fish" or other display aquarium fish to add to their tank.

When they did so, they usually have made a critical mistake...

... Not quarantining.

As a result, the fish can transmit infectious disease to the axolotls, most notably parasitic diseases such as Costia or intestinal worms (nematodes).

These can kill the axolotl.

All new fish should be quarantined for at least 30 days before adding them to an aquarium that contains axolotls.

Ideally, you only purchase fish from a trusted breeder, as some diseases can remain in the fish's body for longer than 30 days and escape the quarantine period.

Other causes of death

The above 5 reasons an axolotl could have died are not the only ones.

There are others, but some of them can be:

  • Accidental injury/trauma
  • Aquarium contaminants/water system flush
  • Rapid temperature swing
  • Wrong medications
  • Rancid/contaminated food source
  • Other illness or genetic issue

Fortunately, these causes are not as common.

What about if an axolotl dies in shipping (or right after being shipped)?

If an axolotl arrives DOA (dead on arrival) after being shipped to you, the leading cause is almost always hypoxia, or oxygen deprivation.

There are a couple of things that can cause this.

Firstly, inexperienced shippers will often assume the axolotl should have lots of water and do not consider the importance of air in the bag. The opposite is true - oxygen is the #1 biggest limiting factor when it comes to shipping live axolotls.

However, even if the bag had the proper ratio of air to water, in high temperatures, this oxygen gets used up much faster and can still cause suffocation. This is why shipping in extremely hot weather is very risky. Sometimes an unexpected heat wave is experienced in certain areas of the country where the axolotl is being transported, which can lead to overheating. Ice packs will not last more than 12 hours under such conditions, even if insulated.

Some think the axolotl didn't use up the oxygen because the bag still appeared to have air in it when the animal arrived, but in reality, the oxygen was used up due to chemical processes inside the confined area of the bag.


If it is within 24 hours of being transferred to the new fish tank, it is likely water parameter shock or improper acclimation. The old parameters may have been far different than the new parameters. Usually, something is very off with the new water the axolotl is being moved to. If the axolotl goes from hard water to very soft water, the axolotl's system can go into extreme stress and shut down.

Never pour the filthy bag water into the tank with the axolotl, as it contains high levels of ammonia which can become incredibly toxic once the bag has been opened.


Sadly there are a number of causes that can kill our beloved pet axolotls, but most of them are preventable. Though it can be difficult to lose your axolotl, sometimes experience is the best teacher and you can learn how to adjust for the future.

Thank you for reading!

Reading next

What is the Best Substrate for an Axolotl Tank?
How to Breed Axolotls

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