Chris,
The best way, and I use it on the main tank here to remove butterflies once their deeds are done is to leave all the lights off till later in the night, then put all the lights on at once. The fish will "wake up" in a stupor and will swim/bump around the tank and are basically blind for a time, and can then be scooped out. If you know where he sleeps, get a piece of rigid airline tubing and encourage him to swim about by gently prodding him from his space. It may take several tries, but it has yet to fail in 20,000 gallons worth of reef. The key is to essentially "blind" them so them light the better.
Joe