Axolotls in Minecraft are new mobs set to be released in the summer as part of the Caves and Cliffs update. They are passive to players. However, an Axolotl will attack other underwater mobs. The two mobs they will not attack are turtles and dolphins. The Axolotl attacks the other mobs as a method of hunting. Their preferred food that players can feed them is tropical fish.
What do Axolotls eat in Minecraft?

Players can use tropical fish and buckets of tropical fish to lure Axolotls. Minecraft Axolotl will not survive on land. However, they can wander on land in the rain or during Minecraft’s stormy weather. However, it is not a good idea to keep Axolotls out of the water.
An Axolotl will typically try to find the nearest source of water when brought to land. If the Axolotl isn’t taking the bait and following the fish, a player can use a lead instead.
Buckets can be used to collect Axolotls the same way a player can to a fish. A baby will still mature in the bucket and may respawn as an adult. However, once they have respawned, Axolotls won’t despawn naturally in Minecraft. This is a common trick used by players to keep fish in flat worlds.