I've seen a young lion fish in a 34g tank with corals, inverts, a (juv) blue hippo tang, firefish, and i think there was a chromis in there. It was a young tank in general but everyone looked happy and healthy. Any one else, maybe some one who has kept them??
I've not had them but I imagine they follow other aggressive fish guidelines. Keep them with other fish that are not so easily bullied. No clue about the reef safe part. I imagine that inverts (shrimp and crabs) are out of the question though.
I have a lion fish, I caught it when it could fit into the top of a coke bottle.
It is placid, you need fish that are the same size or a little bigger that it.
It will grow very quickly!!!
And don't stick your hand in the tank when you don't know where it is. The hospital is a boring place to be on a sunday night. Ha ha. On the up side, I've only done it twice.
Adding color is always nice and tangs seem to be available in all sizes, patterns, and colors. A chevron tang is always bitchin! Good luck finding friends for your lion.
whilst can be small at first, they will grow and eventually anything which is small enough to fit in its mouth will become a nice expensive snack for the lionfish.
IMO these fish are left to predator tanks only (lionfish, eels, triggers etc.)