I had a Volitan Lionfish for about 3 years and gave him away when I decided to go reef. Now I have a large FO(fish only tank) and I'll probably get another one. They are a very personable fish with lots of character. One of my favorite fish. A few things to be carful of. They a very venomous. So stay will away from those "little prickly" fins. They have a wicked sting.
As far as feeding, I got lucky and mine ate as soon as he was in the tank. If you're having trouble getting it to eat you can use live feeders and shrimp to entice it but make sure they are saltwater feeders. Most LFS(local fish stores) have freshwater feeders. They are ok temporarily but will not be good long term for the fish. Mine pigged out on silversides and krill soaked in garlic and Selcon.
A 30 gal is the min size recommended for most lionfish, obviously a larger tank would be better. I kept mine in a 90 and he was very happy.
Here's some good info.
http://www.reefkeeping.com/issues/20...ture/index.php