Minecraft wiki entry for Slime_farming, associated text: The second step in building a slime farm is transportation. In pre-1.8 traps, this is usually achieved by using 'canals' of water separated by signs. As slimes can swim in snapshot 14w06a and above, specific water placement is required in Java Edition 1.8 and above. Or using an iron golem to attract the slime to the killing spot.