Well, there's information enough about the monkfish,
monkfish and it has other( goosefish ) and local names as well, but what surprised me was that the English names are so undescriptive.
I'm a visuality addict and I look at the creature and try to see the monk in it. No way.
Seadevil, Yes! just look at it! (link) The other Dutch name Hozemond (Hugemouth)(or maybe Heavemouth) definitely yes. Online etymology has no aswer (so maybe there isn't) Sobeit!