Is it possible that you have flatworms? I'd look at your corals closer to see if that is the case. If not, you may want to try feeding more often. While I've never noticed any of my wrasses picking at any of my corals including the new SPS I have, they need to eat constantly and should be fed more than once a day. My fish are fed 3x a day. I use autofeeders to do two supplmental feedings a day. Some wrasses are known to eat flat worms so that is also a possibility.