How about taking one of those plastic coral cups with the lid on.. Cut a round hole half way up for the fish to find its way in.. Hopefully they forget how to get out.. Kinda like a wasp trap?
Or one of those clear round sand cleaner tubes.. Plug one end and fill it with mysis and be ready to scoop?
I caught a pesky wrass once by putting a 6" tall piece of PVC Vertically in my tank.. He couldn't stand it and went in to investigate
