Hello!

I'm very much of the same mind as thesweetcheat, in that I always enjoy seeing wells pop up here. They're always welcome in the forums, surely, as their antiquity will be all part of the conversation.

Water sources are often pretty darned old, even if the well houses were built a while after. I remember visiting St Cubert's Well, on the Holywell Bay golf course. The well house was restored in the 1930s from a suspected 15th century enclosure, but the actual wellhead is a very well worn and extremely ancient looking rock. And on the whole I think rocks can be fairly old. ;)

I do actually have a vague recollection of a well which apparently contained a talking trout, but for the life of me I can't remember any details!

I have a feeling it was in Ireland, and having done a little (unsuccessful) search for that particular story, I did find a lot of references to trout in wells and springs over there.

I'll rack what's left of my brain to find the story I'm thinking of. I have several reference books so bear with me. But in the meantime, I stumbled across these, in both Ireland and Scotland, and at least one of which you have also mentioned:

https://www.libraryireland.com/AncientLegendsSuperstitions/Sacred-Trout.php
https://www.truehighlands.com/holy-wells-scotland/#:~:text=The%20guardian%20of%20this%20well%20is%20a%20sacred%20trout
https://voicesfromthedawn.com/tullaghan-hill-holy-well/#:~:text=Another%20legend%20concerns%20the%20pair%20of%20enchanted%20trout%2C%20not%20visible%20to%20everyone%2C%20which%20appear%20primarily%20for%20the%20faithful
https://www.caughtbytheriver.net/2012/06/the-pigeon-hole-holy-wells-and-sacred-trout-charles-rangeley-wilson/#:~:text=Many%2C%20I%20was%20delighted%20to%20discover%2C%20are%20inhabited%20by%20sacred%20fish%2C%20invariably%20salmon%20or%20trout.
https://holywellscorkandkerry.com/on-wells-6-blessed-fish/

This should keep you going for now, at least. I do love me a bit of water-based folklore. It's been a while since I've read up on these though!

G x