I went the bare bottom, nothing but discus route for months!! Every other day water changes etc, etc. I finally got tired of it...hated the way the tank looked and the fish never seemed happy. I had some diamond tetras I had long since quaranitined and I neede the tank space...so I said forget it I'm putting them in with the discus. I had a bunch of white sand I had just bought. I threw the sand on the bottom, put some bigger rocks a few java ferns and the tetras...the discus loved it. They actually schooled instead of staying in a big clump all the time. I put a few harelquin rasboras in as well (after quarantine of course) and it got even better. They just seemed happy for the first time. They ate better, were less aggressive.
So then fast forward a few months...I have moved all my discus and the diamonds and the harlies to my new 150. I buy 6 juvie..2-2.5 inch ..discus. 3 cobalts and 3 blue sapphires. I put them in the now empty, but with sand substrate and a few decorations, 55 gallon. They hide all the time for days. They come out to eat, but that is all. The freak out when I turn on the light...it was not fun. I decided to move the harlies back and see if it made a difference...wow!! It was night and day!!
Made such a huge difference, it was really unbelievable. As soon as quarantine was over I moved them in to the 150...so now I have a mix of sizes which most people say no to...but they have grown like weeds and stand their ground at feeding time.
So, I, based on my personal experience, think Discus actually LIKE and probably NEED some smaller dither fish to really help them feel safe and secure. So, I personally would leave those other fish there. You have had them in the tank with all the other stuff any way. I see no reason to move them.
Steph
P.S. Just my experience and my opinion!!