Axolotl Sexing: How to Determine an Axolotl’s Gender

Male and female axolotl sexing

Axolotl sexing is one of the trickiest parts of owning this captivating amphibian. While determining the sex of many aquatic animals is quite straightforward, axolotl sexing can be a challenge. 

Generally, to determine an axolotl’s gender, observe the cloaca and body shape: males have a swollen cloaca and slender body, while females have a slit-like cloaca and wider body. Males also show courtship behaviors and develop nuptial tubercles, whereas females lay eggs.

If you want to learn more about axolotl sexing, you’re on the right page. This article provides a thorough guide on how to identify an axolotl’s sex, the appropriate time to do so, and other related topics. Let’s start!

When Can You Tell an Axolotl’s Gender?

Axolotl sexing

The question of whether an axolotl is male or female is not one that can be answered immediately after its birth. 

It is generally around six months of age when the physical distinctions between a male axolotl and a female axolotl begin to manifest. 

However, it’s crucial to understand that this timeline is not set in stone. In certain instances, it might take up to a year to confidently tell an axolotl’s sex.

It’s also worth mentioning that axolotls cannot change their gender once it’s established. This is a common misconception due to the gender fluidity seen in some other amphibian species, such as frogs.

Therefore, once you are able to sex your axolotl, you can be assured that the identified gender will remain the same throughout the axolotl’s life. We’ll touch on this topic in a later section of this guide.

How to Tell If Your Axolotl Is a Male or Female

Male and female axolotls in an aquarium

1. Examine the Cloaca

The cloaca, a dual-function organ in axolotls, is instrumental in both waste expulsion and reproductive processes. It exhibits unique characteristics in males and females, which can assist in determining the sex of axolotls.

Generally, male axolotls display a more pronounced and swollen cloaca, simplifying their identification. 

During one of my field studies, I had the opportunity to observe a small group of axolotls in their natural environment. 

The males, indeed, had noticeably larger cloacal regions. In contrast, female axolotls usually have a less noticeable, smaller cloacal area. This can make the task of determining their sex a bit more challenging. 

2. Observe Body Shape

A discernible difference in body shape can help distinguish male and female axolotls. For starters, females usually exhibit a broader and rounder body, especially noticeable when observed from an overhead perspective. 

This is due to their ability to carry eggs, resulting in an evolved body structure to accommodate this task. Males, on the other hand, tend to be slimmer and less robust in comparison.

3. Watch for Breeding Behavior

Males and females behave differently during mating. Males tend to wiggle their tails and go around the tank laying sperm cones everywhere. These are known as spermatophores. 

Females, on the other hand, tend to follow them around, with their noses against the cloaca. Observing these behaviors can help determine the sex of your axolotl.

Here’s a video showing what spermatophores look like — a good indication of whether an axolotl is male or female:

What does axolotl spermatophores look like? Axolotl lays sperm #axolotls

4. Compare Sizes

Regardless of the morph of axolotls, female axolotls generally tend to be larger than males. They have a wider body, especially when they are carrying eggs. 

However, size should not be the sole determinant of an axolotl’s sex, as individual growth rates and sizes can vary.

5. Watch for Breeding Behavior

Male axolotls partake in intricate mating rituals, which include actions such as gentle prodding, nipping, and tail oscillations, all in an effort to draw the attention of female axolotls. 

These behaviors can serve as additional indicators to tell whether your axolotl is male or female. It’s important to observe your axolotl during these interactions as it can provide valuable insights into their sex. 

For instance, the axolotl male or female will display different behaviors. Males often have a more pronounced display, while females may be more passive.

Here’s a video showcasing the mating dance of axolotls:

Axolotl Mating Dance

6. Seek Professional Assistance

If the task of determining the axolotl gender remains challenging even after considering the factors mentioned above, it may be beneficial to seek professional assistance. 

An experienced veterinarian or a proficient axolotl breeder can be of great help. 

They can utilize more sophisticated techniques, such as ultrasound imaging or DNA analysis, like the polymerase chain reaction (PCR) procedure. However, it must be noted that these are not common practices.

Furthermore, keep in mind that the process of sexing an axolotl can be complex, especially for a juvenile axolotl. 

Axolotls reach sexual maturity usually between the ages of 6 and 12 months, and it can be impossible to sex them accurately before this period. 

Can an Axolotl Change Its Sex?

Axolotl in a tank leaning on a rock

The straightforward answer to this question is no. Axolotls can’t change their sex. This is a characteristic that sets them apart from some other members of the animal kingdom. 

For instance, certain species of fish, reptiles, and even amphibians have the remarkable ability to alter their sex during their lifetime. However, axolotls, despite being amphibians, do not possess this capability.

The gender of axolotls is determined genetically at the time of fertilization and remains the same throughout their life. 

This is a fixed trait, much like the unique features on an axolotl’s back legs or the toe tips of lighter-colored axolotls. 

In other words, it’s a common misunderstanding that all amphibians can change their sex, but this is not the case. Axolotls are among the amphibians that do not have this ability.

It’s worth noting that the ability to change sex is quite fascinating and is found in creatures like clownfish and some species of frogs. 

The clownfish, for example, live in groups where there is a strict dominance hierarchy. If the female at the top dies, the most dominant male changes sex and takes her place. 

Frequently Asked Questions

Two axolotls looking out of their tank

Can You Sex a Baby Axolotl?

Identifying the sex or gender of a baby axolotl is a significant challenge due to the absence of clear physical traits related to gender during their early lifecycle. Their gender becomes more apparent as they grow older.

Typically, an axolotl is sexually mature and ready for sexing around the age of six months to a year. This is the period when you can tell whether an axolotl is a boy or a girl.

Are Male or Female Axolotls Bigger?

In general, female axolotls are larger than their male counterparts. They possess a broader body, particularly noticeable when they are carrying eggs — an indicator that your axolotl is ready to breed. 

However, size and behavior should not be the only factors considered when trying to tell the gender of an axolotl. Individual growth rates and sizes can vary significantly among axolotls. 

Can You Keep Male and Female Axolotls Together?

Yes, male and female axolotls can live together harmoniously. However, if you decide to house them together, be prepared for the possibility of axolotls breeding. 

Ensure you have the necessary resources and knowledge to care for potential offspring.


Remember, each axolotl, regardless of its gender, is unique and deserves care and attention. If you have any thoughts or questions about the topic of axolotl sexing, leave a comment below!

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