Treatment. Cleaner wrasse should never be kept in home aquariums.
They have extremly narrow digestive patterns and thus you usually find that most will wither and die within 6 months due to starvation. There are a few exceptions of course, I have known of a few hobbiests that have kept them successfully but in the majority of cases these fish simply cannot adjust their digestive systems to normal aquarium food sources.
Cleaner wrasses also tend to harrass fish and make the white spot problem even worse. In the wild they have cleaning stations where fish come and go all day long. In the tank these fish cannot get away and the wrasse continues to target them.
Use treatments/UV/Garlic/Ozone, its the safest way IMO