Do Axolotls Die Easily? 10 Common Threats To Your Axolotl’s Longevity

Figuring out whether your axolotl is male or female can be tricky, especially when they are young. Unlike some animals where the differences are obvious from birth, axolotls do not show clear gender characteristics until they reach sexual maturity. But once they do, there are some reliable ways to tell males and females apart.

When Can You Tell an Axolotl’s Gender?

You generally cannot determine an axolotl’s gender until it reaches sexual maturity, which happens around 12 to 18 months of age. Some axolotls mature faster than others depending on their diet, water temperature, and genetics, but trying to sex an axolotl younger than about 9 to 12 months is usually not reliable. If someone sells you a baby axolotl and guarantees its gender, take that with a grain of salt.

At around 12 to 18 months, the physical differences between males and females become much more apparent. Here is what to look for.

The Cloaca: The Most Reliable Indicator

The single most reliable way to determine your axolotl’s gender is by looking at the cloaca, which is the opening on the underside of the body between the back legs. In males, the cloaca area becomes noticeably swollen and enlarged once they reach maturity. It looks like a rounded bulge that is easy to see when you look at the axolotl from the side or from below.

In females, the cloaca area remains flat or only slightly raised. There is no pronounced bulge. This difference is the most consistent and reliable way to sex axolotls, and once you know what to look for, it is usually pretty easy to distinguish between the two.

Body Shape Differences

Beyond the cloaca, there are some general body shape differences between male and female axolotls. Males tend to have a longer, more slender body shape. Their heads are often slightly narrower relative to their body compared to females. Overall, mature males have a more streamlined appearance.

Females typically develop a rounder, plumper body shape, especially when they are carrying eggs. Their bodies tend to be wider and more robust, particularly through the midsection. When a female is full of eggs, the difference in body shape compared to a male is quite dramatic.

However, body shape alone is not a reliable method for sexing axolotls. A well fed male can look plump, and a female that is not carrying eggs can look relatively slim. Always use body shape in combination with the cloaca check for the most accurate determination.

Tail Shape

Some experienced axolotl keepers also note differences in tail shape between males and females. Males often have a slightly longer tail relative to their body length, and the tail may appear flatter. Females may have a slightly shorter, rounder tail. These differences are subtle and are best used as supporting evidence rather than a primary identification method.

Behavioral Differences

While behavior is not a definitive way to determine gender, there are some patterns that can offer clues. Males that are ready to breed will often deposit small white packets called spermatophores on the tank floor. If you see these jelly like cones in your tank, you definitely have at least one male.

Females that are ready to lay eggs may show nesting behavior, spending time near plants or decorations where they plan to deposit eggs. They might also look noticeably rounder as they fill with eggs. However, females can absorb eggs that are not fertilized, so the absence of visible egg production does not rule out a female.

Common Mistakes When Sexing Axolotls

One of the biggest mistakes people make is trying to determine gender too early. A six month old axolotl simply has not developed enough for reliable sexing. Be patient and wait until at least 12 months before drawing conclusions.

Another common mistake is relying on size alone. While females do tend to be slightly larger than males on average, there is enough variation between individuals that size is not a useful indicator by itself. A large male can easily be bigger than a small female.

Color and morph are also not indicators of gender. Male and female axolotls come in all the same color morphs, and there is no color that is exclusive to one sex.

Does Gender Matter for Pet Owners?

If you are keeping a single axolotl as a pet, gender does not really matter from a care standpoint. Males and females have the same care requirements, eat the same food, and live equally long. The main time gender becomes important is if you are keeping multiple axolotls together, because a male and female pair will eventually breed, which means you will have eggs and potentially hundreds of baby axolotls to deal with.

If you want to keep multiple axolotls together without breeding, keeping same sex groups is the safest approach. Two females or two males typically coexist without issues as long as the tank is large enough and they are similar in size.