Axolotl is a passive aquatic mob found in lush caves. It hunts most other aquatic mobs, assists players in combat, and grants Regeneration. Axolotls can be carried in a water bucket, making them portable allies in underwater battles. Axolotls do not drop any items upon death but grant 1–3 experience when killed by a player. Axolotls can be bred using buckets of tropical fish. When two adult axolotls are fed, they enter love mode and produce a baby Axolotl, granting the player 1–7 experience. The baby inherits the color of one parent at random, but there is a 1⁄1200 chance of hatching a rare blue Axolotl. Baby axolotls take 20 minutes to grow into adults, but this time can be accelerated by feeding them buckets of tropical fish, reducing the growth time by 10% per use.

Axolotls are passive toward players but attack most aquatic mobs, including squids, glow squids, tropical fish, cod, salmon, pufferfish, and drowned, dealing 2 hearts of damage per attack. They do not attack turtles, dolphins, frogs, or other axolotls. If a player kills a mob that an Axolotl is fighting, the player receives Regeneration I. Additionally, axolotls remove Mining Fatigue from the player, making them useful for raiding ocean monuments. Axolotls can be attached to leads and will follow players holding a bucket of tropical fish. They play dead when injured, regenerating health while hostile mobs ignore them. This makes them resilient and effective in underwater combat.