I have mine juvies in a barebottom with Rummynose Tetras, Otos and some endlers. It's much easier to keep the tank clean and feed 5 - 6 times a day when they are still so small (less than 6 inches).

Once they are adult, I'll move them into a planted tank with a substrate. I lost way too many discus not going barebottom from the get go.