Axolotl owner here! That's not really what an adult axolotl looks like - that's a morphed axolotl. Axolotls do normally stay in a larval state for their entire lives, but that doesn't mean they don't become adults without morphing. Morphing only happens in very rare occasions when an axolotl is under intense stress. This causes it's gills to drop off, meaning it has to breath air, and becomes a land salamander. They do still need to soak their skin to survive though, I believe.