Cute!!! I used to occasionally get ducks in my pool too - I'd snap a picture then open the back door which would shoo them away, LOL.
Mostly we got frogs in our pool. In the spring I had to make sure to check the pool every morning before the filters kicked on or I'd find frog corpses in the filters. I love frogs so I enjoyed my morning frog-rescuing routine. Found at least one frog just about every morning, and a few times I caught a couple of them trying to spawn!