What Tangster says is very important.
If fish is hiding out, it is for important reason.
Will show back up eventually and if it does not, keep eye on hermits. If they all have seemed to disappeared also, expect the worst...
I guess I should have noted that I was looking for a fish that swam to the big ocean in the sky when I said moved my rock in my 37 gal. I've only had to do that twice, and I still couldn't locate the remains of my scissortail goby. I'm in the process of setting up my 90 gal - has a built in overflow (so anticipate plenty of plumbing/refugium questions soon 
) so I haven't even ventured into reefland yet. I've got FWLR, snails and a peppermint shrimp that I'm looking to move into the 90 eventually.
Thanks Tin, I like your work. How do you stabilize the rock that high? I've seen people put pvc pipe through the rock, but how do you drill through live rock?
Sorry for all the questions, but I've gotten some helpful advice on this forum and want to make sure I'm doing things right the 1st time with the reefing.