Is the turtle a threat to my fish (just stocked this spring 450 total fish)? .
In the words of good ole Uncle Bill (Dance), and I quote, "If a turtle eats a fish, the fish deserved it".
They are merely a part of the ecosystem.
He is of no threat to your fish population, IMO.
There is, or at least was, an American Alligator Snapper on display at the Fair Park Aquarium in Dallas for as long as I can remember. This ole boy was around 200lbs, and BIG!!! I used to stare at that turtle for ever it seemed. For some reason I have always been facinated by the snappers.
