Disappearing wrasses

[Coralgurl]

I bought a mystery wrasse on boxing day, acclimated and added to the tank. Saw him the next day and been missing since. Last weekend I added a radiant wrasse, same thing, saw it Monday morning and haven't seen it since. Yesterday, I noticed my solar wrasse is missing a chunk out of his tail fin. I don't think the other fish are causing problems....I had a funky red crab in the tank somewhere but no clue where it is..wth? I know wrasses can hide for a while but this is frustrating!