No killer fish!
I have not seen (or heard) a bullfrog in my pond ever. I've only got the black frogs with the green head, and the largest is only about 3 -3.5 inches from nose to butt when sitting, and when I do get tadpoles, they're very small. I don't know if they're playing in the waterfall and getting swept in or not. I've only netted the pond once, but that was about 3 years ago in the fall.
Thanks everyone!