My Mum used to say it, and I think her Mum did too. My Grandmother was Welsh, but lived in Somerset, England since she was young, then moved to Australia. We are in NSW, Australia.

(Slight thread creep: My Grandmother also used to say "Ach y fi", pronounced Uck-a-Vee, with the emphasis on Uck, which apparently is an expression of disgust, and another saying, when she was trying to do something and it wasn't working, which sounded something like Doo-a-na-la-beat (with emphasis on Doo & beat). I can't remember it exactly, and have no idea of the correct spelling or what it means.)

I'm surprised that the answer to the question about gods & fishes is so elusive. It's a mystery that, as far as I can see, even Mr Google cannot solve - yet, although I only dipped my toe in the pool of information & speculation on the issue.

Helen