Getting a pr of cleaners is difficult, as they dont tolerate other cleaners.
In the wild they are in pairs, but are not communal as other wrasses are in that there will be a population of juveniles nearby. When they settle from larval stage they begin their transition to adulthood. They either find a location to set up their own cleaning station, join an unpaired cleaner, or die. Once they establish their station they will quite vigorously defend their it from other cleaners. So, unless you are able to find an already bonded pair, the likelihood of pairing them on your own is very low.