Axolotl

Axolotls are passive aquatic mobs.

Spawning
Axolotls do not spawn naturally in the world, being only available from buckets or spawn eggs in the Creative inventory.

Variants
Axolotls come in five different varieties: cyan, gold, lucy (pink), wild (brown), and blue. The first four varieties are equally common, while the blue variety is rarer. Specifically, the blue variant has a $1/1200$ (~0.083%) chance, giving the common varieties a $1199/4800$ (~24.98%) chance individually.

Axolotls picked up and re-spawned with a bucket will not preserve their color.

Behavior
Axolotls are passive to players. Axolotls are intended to give and remove  when a player kills a mob that an axolotl is in combat with; however, this currently does not work.

Axolotls are always hostile to fish and squid and attack these mobs on sight. Axolotls will only attack drowned and guardians when tempted with tropical fish by a player. Drowned and guardians will always attack axolotls on sight.

As axolotls are aquatic mobs, they take extra damage from tridents with the Impaling enchantment.

If an axolotl takes damage, it may pretend to be dead, dropping to the ground for 200 tick and gaining the I effect if in water. Monsters will ignore recovering axolotls. For an axolotl to play dead, the damage must not be from drying out on land, and there is a random $2/3$ chance for the axolotl to not play dead. In addition, if either a random integer from 0–2 (inclusive) is less than the amount of incoming damage, or the axolotl's health before the damage is dealt is less than 50% of its maximum health, it then plays dead. Internally, they will not attempt to play dead if the damage will kill them, though this has no effect since the axolotl will die either way.

On land, axolotls try to move to the nearest water source because they die outside of water after 6000 tick. Axolotls do not die on land if the weather is rain or thunder.

Axolotls can be attached to leads.

Breeding
Adult axolotls can be led and bred with tropical fish or buckets of tropical fish. After breeding, a baby axolotl spawns and the parents cannot breed again for 5 minutes and 1–7 experience is spawned. The baby axolotl has a $1/1200$ chance to be the rare blue variant; otherwise, one of the parents' variants will be selected at random.

Entity data
Axolotls have entity data associated with them that contain various properties.

Trivia

 * Axolotls are small Mexican salamanders which are critically endangered, following Mojang's trend of adding endangered species such as giant pandas and bees into the game for awareness purposes.
 * Their regeneration abilities allude to their real-life regeneration capabilities, which are of major interest to science.
 * Axolotls are the first amphibian mobs implemented into Minecraft.
 * However, it was not the first announced one since frogs were announced at MINECON Live 2019.
 * Blue is the only color variant of axolotls that are not based on real life.
 * Rather, it seems to be based on the Pokémon Mudkip, which itself is based on real-life Axolotls.