In Minecraft, a villager becomes a fisherman when it claims a barrel as its job site block while it is unemployed and has access to an unclaimed bed in a village.
Basic requirement
A fisherman is not a special villager type at spawn; it is just a regular villager that has taken the fisherman profession.
For this to happen, the villager must be unemployed (no existing profession) and able to pathfind to a free job site and bed in a valid village.
Job site block
The specific block that makes a villager a fisherman is the barrel.
When an unemployed villager links to an unclaimed barrel, the game assigns it the fisherman profession and updates its appearance and trades accordingly.
Visual and trade changes
Once converted, the villager gains fisherman clothing (often brown with a straw hat and a fish on its belt) and a fisherman name internally.
It will then offer fishing‑related trades such as buying fish and boats and selling cooked fish and enchanted fishing rods, which improve as its profession level increases.
