Yah, I have been told from many places that cleaner wrasses do not survive well in captivity, few weeks can die off. Mostly because they refuse to feed on commercial food, and there is not enough parasite infested fish in marine tanks to keep them fed after a while. In the wild, cleaner wrasses clean a LOT of fish, much more than you can hope to put in your tank, so don't imagine being able to keep one for one.