I would do a sulawesi tank, a very prettily dragon-cave tank and put a betta in as a dragon and some h. formosa in as its minions, or I would just soften my water and go with P gertrudae. Also, maybe a killi breeding tank.
I love darters and Pygmy sunfish, and som shiners/minnows are very beautiful, also, so maybe a mini native tank. Melatanistic Gambusia are very pretty...
And there is also the option of show guppies.
I need more tanks.