Poison Protection I-IV

Obtained by trading with a Librarian (random) OR master fisherman (as they deal with string and pufferfish). It would be equipped to any piece of armour but would be incompatible with other protection enchantments. It would share similar mechanics to other protection enchantments whereby each level reduces the damage done and level IV would give immunity. There could be a very small chance of finding it in mineshaft chests. Items enchanted with poison protection could also possibly have a green glow instead of the bluish glow already in place from other enchantments.