I put in a pond last spring. Small, preform black pond. Filled it, threw in some duckweed, some floating plants from some ditch or another (I'm very keen on gardening on the cheap) and a hideous, overly expensive water plant from a garden store(so I had a weak moment), and mulled getting livestock. Before I could so much as windowshop goldfish, two large bullfrogs appeared out of nowhere.

I love how frogs can do that. Somehow, despite the near-total lack of froggy habitat nearby (my neighbors have inground pools, playsets, basketball courts, etc.) and a whole lot of traffic, they seem to appear out of the sky whenever water collects for more than 5 minutes.