Does anyone have a clue as to why this may be? It would seem to be the
next piece in the jigsaw to look at.
> are descendants of my original wild stock and I think the US fish came from
> Europe (Peter???).
Correct.
> It may well be that this species was on its way out anyway
> despite help from the gambusia?
Could well be that it is working with a disadvantage. Mind you, under
appropriate conditions they can be quite abundant.
Cheers
Peter Unmack