Do axolotls breathe like humans with their lungs or like fish with gills? The reality is a bit more complicated.
Axolotls have 4 different methods to breathe, with their gills, skin, lungs, and throat (Buccal pumping). Their gills are the most noticeable of these due to the fact that they are not internal in the body, but are external gills.
How do axolotls breathe?
Axolotls can breathe in 4 different ways, but they primarily use their gills and skin to take in oxygen.
1. With their gills
The gills of axolotl immediately catch everyone’s eye, because compared to fish, they are not inside their body, but on the external gills. The gills of Axolotl are located on the back of their head and can even grow back if they are damaged or bitten off. They have 3 gill branches on each side of their head that split into finer structures.
With its gills, the axolotl absorbs oxygen from the surrounding water and releases CO2 back into the water.
Water flows through the gills and allows oxygen to pass through the gill membrane into the axolotl’s blood, whereas CO2 diffuses out of the axolotl’s blood into the surrounding water.
To allow fresh water with higher oxygen content to reach the gills, the axolotl regularly flaps its gills. Here is an article where you can learn more about the special gills of the axolotl.
2. Through their skin (skin breathing)
Another way axolotls breathe is through their skin, also called Cutaneous respiration. In this process, they take in the surrounding oxygen from the water directly through their skin.
Because axolotls have very thin skin, small gas molecules can easily pass through it and are absorbed into their blood.
Skin breathing is also common in other amphibians, frogs, toads and salamanders also breathe through their skin.
3. With their lungs
The lungs of axolotls aren’t well developed compared to land animals and are rather simply structured. But it is a good way for them to breathe when the oxygen level in the water is too low.
In order to breathe with their lungs, axolotls swim to the water surface and swallow air. Then, after the lungs have absorbed oxygen, axolotls “burp” the air back out of their mouths.
If your axolotl regularly swims to the surface of the water to breathe with its lungs, you should check the oxygen levels to be sure. However, it is also possible that your axolotl simply enjoys breathing with its lungs and floating around the aquarium a bit with the air bubble in its body.
4. Buccal pumping
In the throat, axolotls have a flap of skin that can also absorb oxygen from the water, just like their skin. The membrane is called buccopharyngeal and is common in some amphibian species.
Do Axolotls need an oxygen pump or an airstone?
No, Axolotls don’t need an extra oxygen pump or an airstone, the filter should get enough oxygen into the water. Nonetheless, to make sure your Axolotl has enough oxygen, you can make sure the filter swirls the surface a bit or add some plants to your tank. Here is an article with the best plants for an axolotl aquarium.
How does oxygen get into the water?
There are several ways that oxygen can get into the water of your Axolotl aquarium.
Via the water surface
Oxygen molecules enter the water through movement on the water surface and the larger and more turbulent the water surface is, the more oxygen is absorbed.
Oxygen pump or airstones also work by the same technique.
Via the filter
The filter not only ensures good water quality, but also the absorption of oxygen into the water. The movement of the water and the current increases the oxygen concentration in the tank.
Via plants
The plants and algae growing in your tank produce fresh oxygen for your Axolotl to breathe. Plants also provide a natural environment and hiding places for your axolotl.
How do I know that there is enough oxygen in the water?
You can check the oxygen concentration in the aquarium with a water test*. Generally the oxygen level for Axolotl should be above 6 mg/l. A good oxygen level is 6 to 8 mg/l.
However, you can also look for other signs without a test that indicate that the oxygen concentration in the water is sufficient. The axolotl…
- eats enough
- has a healthy skin color
- does not show any sudden changes in his behavior
Why do axolotls have lungs and gills?
Fish have only gills and salamanders only lungs, but why does the axolotl, which lives only in water, have both?
Axolotls remain in the larval stage throughout their lives, another word for this state is “neoteny”. If they were to morph up, similar to other amphibians e.g. frogs and salamanders, their external gills would regress. And they would change from living in water to living on land. Therefore, axolotls already have the lungs they would need to live on land as their salamander-like form.
Can axolotls breathe outside of water?
Yes, although axolotls are purely aquatic animals, they can breathe outside of water with their lungs. But their lungs aren’t very efficient and that’s why they only breathe with their lungs rarely.
To do this, they swim to the surface of the water, swallow air and pass it into their lungs. Due to the air bubble in their body they then float through the tank for some time until they release the air with a “burp”.
Conclusion
Axolotls can breathe not only with their gills but also through their skin, throat and lungs. In order for your Axolotl to be able to breathe well, it is important that the water parameters are correct and the oxygen concentration in the aquarium is high enough.