When we first put our pond together we put in a couple of tadpoles. They grew into huge bullfrogs. Eventually one of them ran away from home and was never seen again. The other one made the mistake of playing with Pooka, but I actually think he was already ill because he kept leaving the pond, or maybe he had just grown too big for our pond. Anyhow, the playing with Pooka is what I guess killed him, but I didn't actually see any marks on him. That was over 3 years ago and we decided not to get anymore frogs.
Last night we were shining a flashlight into the pond to check on the fish and there was a bullfrog of all things. Too small to be the one that ran away from home, but it has apparently taken up residence in the pond. There is a fence around the pond now to help keep the raccoons away from the fish, so if it doesn't wander too far it will be safe from Pooka. I love frogs, so it is fine with me if it moves in, but I can't imagine where it came from. Hopefully, I will get to see it in the daylight sometime soon.