I recently bought a 50 gallon aquarium that has a second level built into it about halfway up. The idea is to have water in the bottom and a terrestrial area on top, with an aquarium filter creating a waterfall in between. I have some killifish I'd like to keep in the bottom (they're about 2"-3" fish, very fast).
Can you recommend any interesting amphibian species that might do well in this display? (and not eat my Killies) I can build a bridge from the land to the water, or not, as appropriate.

