How long will a Royal Gramma hide?

[BlueAbyss]

I acquired a 1.5 - 2 inch Royal Gramma about a week ago. In the bag, the temperature had dropped to 70 degrees over about 11 hours. I acclimated him relatively slowly, around an hour... warming up to 80 degrees. In retrospect, that was too fast... too late now, and good thing this is a 'hardy' species...

Anyhow, when introduced to the tank, he went straight into the rock. Found a cave at the back of the large rock, and hasn't moved much since. Last night, he was sitting in the lower cave under the same rock (the caves connect at the back and run up the back to the top of the rock). I observed that his left eye is clouded, and he seems to have some damage on that side of his face. I attribute this to the fact that he was attempting to wedge himself into the corner of the bag that he was in... whoever bagged him in Saskatoon must have forgotten to tape the corners of the bag. He seems to be healing (I noticed the damage the day after he was in the tank, but never noticed the clouded eye). The tank was transparent all the way around until today, when I put some blue paper in behind the back to hopefully make him more comfortable. I have noticed him eat some of the mysis and white shrimp I've been feeding, so he is still eating... not sure if he ate today though.

My question is, how long will this fish stay holed up back there? It's difficult to impossible to target feed him in that particular spot though the current through there is relatively brisk, and brings some of the food through there. Will he ever decide to cruise the tank, or will my fish never venture more than an inch or two from his cave?