I once had to get rid of 3 sixline wrasses, and I found it very easy to trap them in a homemade trap. Here's how to build it:
Take a 16oz plastic soda bottle, remove the labels, and cut off the top (essentially, cut the bottle in half), then turn the top part around and stick it back in the neck of the bottle the wrong way (with the opening facing back into the body of the bottle). Drill some holes in the bottom and all around, and you've got your trap. Place some food in there, and I bet you'll have that bugger in a couple of minutes. If the opening looks too small for your fish, you can easily widen it by cutting some of the neck of the bottle off.
Steve