Mine used to sleep on my monti, he has since moved to the other side of my tank and has a perch on the rocks that isn't near a monti.Interesting....I thought it was so odd mine started doing that, he used to back into a hole in a rock forever (2+years) ...and then all of a sudden one night I saw him do the same into the monti. I kinda laughed to myself because I thought it was because he wanted to be first in line for food in the morning, since my monti is at the top of the reef, and the rock he used to sleep in was in the back on the bottom...
So cool yours does it too!!
Anybody else notice this??