I’ve seen raccoons, foxes, even cats crawl out on to rocks in a stream, and dip-fish from the rocks, but have never seen them jump into the water, after fish. 2-4ft just isn’t probable for a fox, unless you have a boulder in the shallow end from which it can platform fish.
Did you go out after the fox left and see if he left any wet tracks on the stones? Count the fish?
Darn, I missed the concomitant thing; was outside with a neighbor’s problem rifle.
Single payer = NHS socialized medicine.