I used to have rainbow fish with discus in my grossly underacheiving freshwater tank. For some reason, I could never do freshwater as well as reefs. Go figure
Rainbowfish wrok! I've got 3 M.boesemani, a M.praecox, G.incisus, G.wanamensis and a couple siverdollars in my FW tank currently. I can't wait to add some some G.multisquamatis and M.parkinsoni to the tank when I upgrade.
I'd also love to setup a tank featuring some of the blue eyes like P. connieae, P. furcatus, P. tenellus, and P. gertrudae.