Like the other person said, a queen angel will get to 18 inches and will get too big for the 90 gallon by itself. I got a Majestic angel for my 90 gallon as it is one of the smallest of the big angelfish and only maxes out at 10 inches and is not a fish that needs as much swimming room as some others. Mine is kind of docile and laid back. I hope you plan to get a bigger tank in a couple of years for your guy. I was going to get another fish like a yellow eyed tang to put in the 90 gallon too, but decided to let my Majestic angel be the king of the tank with a bunch of smaller fish. He does not bother the smaller fish unlike himself. I don't know about a queen angel though. They say only one angel per tank, but you can usually mix one large angel with one pygme of a much different color and size without problems. My Majestic angel does not bother my little flame angel at all. A colorful fairy wrasse would be nice with it. Good luck, Lesley