That's a great tank! Why don't you stick a salamander in there once the fish get bigger?
I tried a native tank from my pond... But it smelled too bad, so I eventually removed it, though I really did enjoy it. Actually, I've done a couple of pond tanks. In the first tank all the fish were wiped out by carnivorous insects (Sweet!) but in the second I focused much more on microscopic and teenie organisms rather than fish.