Differentiating axolotl sexes can be difficult at times, here I hope to list a few pointers on how to sex your 'lotl -
Female axolotls generally have rounder, plumper bodies, due to them holding eggs.
Males tend to have a longer body and tail then females.
The most reliable way to tell whether your axolotl is male or female, is to look at their cloaca (vent). The male's cloaca is swollen, while the female's has only a tiny bump, if one at all.
Female axolotl -
Male axolotl -
When lighter coloured axolotls (albino, golden and leucistics) reach sexual maturity, their toe tips turn dark brown/black.
Darker coloured axolotl's (melanoids and wild types) toe tips become slightly lighter to the rest of the body after maturity. Although, this is quite hard to see, while lighter coloured axolotl toes tips are quite obvious.
Lighter toe tips -
Ignore the fungus in the photo above, it was taken the day I first brought home Sonriente; yet you can see the lighter toe tips.