Minecraft wiki entry for Advancement_guide, associated text: Next, you need to find an axolotl. Axolotls usually spawn below sea level (Y=63) in water in total darkness and where there is stone, deepslate, andesite, diorite, granite, or tuff less than 5 blocks below the spawning space. You can encounter them usually by going caving and encountering a water source/water in a cave, or finding a huge body of water underground.