As the owner of a 240 gal., and 2 - 125 gal. packed with discus, I can tell you that small fish like tetras don't add a whole lot to the looks of larger tanks containing discus. The size of the discus as adults is all you really notice. I would go with just discus and a few bristlenose plecos if it were me. Maybe with a few angels if you like. I know you will enjoy the project. Discus are addicting. I started out years ago with only 4, now I have around 50 counting the breeding pairs. I have to keep selling and trading them so I can make tank room for more!