Pictures of the tang would really help us out. As far as a cleaner wrasse, I say no. They either should be left in the ocean, or in a very large system with "tons" of fish. Here is a great thread on exactly what you are asking: http://www.3reef.com/forums/general-reef-topics/do-cleaner-wrasse-eat-ich-99867.html Here is an excerpt: (3) Cleaner Wrasse (Labroides Dimdiatus) and Cleaner Shrimp (Lysmata Amboinensis) eat Ich- WRONG. Wrasses and shrimp eat necrotic tissue, damage scales, and scabs. It has been well documented that the symbiotic “cleaning stations” in the reefs by wrasses and shrimps are there to help heal wounds from carnivore attacks, territorial fights, and other skin/scale injuries. It is possible that these cleaners might knock the parasite off the fish while doing this, but do nothing to control the reproduction and life cycle of Ich in your aquarium. And finally, I would never add a fish into a system where one or more fish was infected with a disease. This will either stress out the infected fish further and/or get the new fish infected (which is probably likely due to the stress of acclimating to a new tank and environment). Just another case of a LFS either not being educated or trying to make a sale (or some combo of the two).