I've never been able to catch mine without draining to tank to the bottom 1". I swear he just morphs into solid rock when it suits him. Several tank moves have involved crab's method of just magically finding him in the new tank via having hitched inside some rock that gets moved over. I even tried the fishing hook and mysis trick, you can read about that little escapade here, I caught everyone except the wrasse .. and .. when I say "everyone" I include myself in that grouping.
Hardest fish I've ever had to catch. Good luck, you're going to need it!!