I don't see any problem with that. They require a large tank(70gal), but you should already have a large tank if you have a tang, so this should not be a problem. If you can, get a juvenile or a female, as they acclimate better. HTH
I think I remember your saying your tank was a 55 gal. A square pink can grow up to 5 inches and you would need a larger tank to keep it healthy and happy. HTH
