I would not do that, It's cool to have your fish to be able to see you and be "involved". Your tang will get use to you in time and come out in the open. If you have to be stuck in a glass box, you should be able to see outside(and think) outside the box.
It's really neat when a fish follows you around
Tank: 55 Gallon
The equipment: Coralife 4x65w (2x10k; 2xActinic), Emperor 400, 2 PH
The Fish: black maroon clown, neon goby, yellow watchman goby, 3 blue-green chromis, royal gramma, and a yellow clown goby.
The Coral: zoos, kenya trees, shrooms
, leathers, hammer, and star polyps
The Inverts: LT anemone, pistol shrimp, urchins, etc.
The Janitors: nassarius snails, turbos, hermits, several brittle and serpent stars
The Rock: 68# of Keys-12# Base Rock; from LR