Thanks for all the help guys... still a bit of a mystery. I'm very sure about the isolation factor of the pond, and very few people in this area fish with minnows (in fact, I've never actually 'seen' anyone fish with minnows anywhere in our river system, although I won't say that it doesn't happen). The nearest stream with a sucker population is a couple of miles away.
I agree that the chance of a bird dropping a fish into the pond is very slim.
Perhaps someone has dropped a pail of minnows in...seems weird to me, but no other explanation seems to fit.
Thanks too for the good news regarding interactions between these species. I guess I'll just see where this goes from here.

Last edited by LongReacher; 07/02/12 08:25 AM.