The title made me crack up. But, in reality, i would make a tank like this:
Lots of plants
Several Large Discus
Maybe a few angelfish
Large shoals of Cardinal Tetras
Large shoals of Lemon Tetras
A big school of Corries
Maybe a few smaller apistogramma's
Tropical freshwater forum.... but I gotta say if a new 5ft dropped into my lap... would instantly convert it to saltwater to upgrade my reef as I already have my 125G cichlid set-up.
But if it has to be fresh, I would look into some rare schooling community fish as I've never had a tank with large schools of fish... closest I've come is my group of sd's and giant danios... not exactly the rarest fish you can think of