I got a midas and a small sailfin (thought it was a bi-color when I first got him) in a 155g. Every so often the larger midas (twice the size) would chase the smaller sailfin, but only for short bursts to claim his territory.
I'd go for it. Plenty of rocks for both to perch on right?
"Life may not be the party we hoped for but while we are here we might as well dance!"