what makes a villager a fisherman

A villager becomes a fisherman in Minecraft when it links to an unclaimed barrel as its job-site block, while also having an available bed in the village so it can take the profession.
Core mechanic
- An unemployed or nitwit-looking villager will turn into a fisherman when it successfully claims a nearby barrel as its workstation.
- The villager also needs a valid bed and to be part of a village (so the game can assign it a profession properly).
How to make one a fisherman
- Place a barrel near an unemployed villager, then wait a few moments for it to link and change outfit to the fisherman skin with a straw hat and fish on the belt.
- If the villager already has a different job, break its current job block (like a smoker, composter, etc.), then place a barrel so it can switch to fisherman instead.
Why villagers “keep turning into fishermen”
- Any villager that can’t reach its own job block may wander and claim the closest available barrel, automatically becoming a fisherman.
- Having random barrels around trading halls or villages often causes unwanted fishermen, so players usually remove or isolate barrels used only for storage.
Quick forum-style note
In many recent forum and Reddit discussions, players confused composters and barrels, but in current versions it is the barrel , not the composter, that defines the fisherman job-site block and triggers the fisherman profession when claimed.
TL;DR: What makes a villager a fisherman is claiming a free barrel (its job-site block) while being an eligible, bed-linked villager in a village.
Information gathered from public forums or data available on the internet and portrayed here.