I've tried:
/summon Villager ~ ~1 ~ {Offers:{Recipes:[{maxUses:10,buy:{id:388,Count:5},sell:{id:**349**,Count:3}}]}}
but he only sells regular raw fish.
I've even tried "349:3"
,"#0349/3"
, even "minecraft:fish 1 3"
But always, he either gives me raw fish, either nothing (just empty slot, game crashes when this slot "bought") So, is that possible? Same thing goes for colored wool/clay, I believe.