I think you should definately consider doing an Asian blackwater tank with Sundadanio axelrodi (if you can find them of course!). Other fish you could have in it are CPDs, Mosquito Rasboras, Boraras maculatus, Danio tinwini, Trigonopoma pauciperforata (you can purchase these at Oraganism, and they are very high-quality), Trigonostigma hengeli and Trigonostigma espei.