The tank is at Kona Grill in Cherry creek. We're transitioning to a reef but the owner wanted these guys out. A foot long is a stretch. These are the Argentus species.
FinsUp, you're right. They are nonstop. Never hiding. Even when catching they never hid once. Very active and open swimming fish. Lots of people on the forums here with 125g plus size tanks, myself included, but getting them a tank with enough swimming room is the key. A 180 with full reef and rock work leaves them little room to swim. These guys unfortunately came from a minimal rock work 20ft long tank swimming all day in a 7000gph current.
Had these guys been 1" I'd say throw in any 125+ and they'll adapt to the environment. But because of where these came from, id be cautious putting in anything smaller than 150-200. Not for fear of fish or coral, more so of the rock work because they are big and strong enough to move rocks or knock them over if wanted.
Size wise they are a weird shape. Google "mono argentus" and look at the liveaquaria size for how their shaped. They're probably a good 4-5" long... But height is closer to 7-8" on the biggest one.