Scientific name: Labroides phthirophagus
Taxonomy: Kingdom Animalia → Phylum Chordata → Subphylum Vertebrata → Infraphylum Gnathostomata → Parvphylum Osteichthyes → Gigaclass Actinopterygii → Class Actinopteri → Subclass Teleostei → Order Eupercaria → Family Labridae → Genus Labroides
Locations: Hawaii
Group: Marine Life → Fish → Wrasses
Fish will visit the wrasse's territory and hold still to be cleaned. Some other species clean, mostly as juveniles, but the Hawaiian cleaner wrasse is the only fish in Hawaii that does it full-time. I've got a whole page of pictures of Hawaiian cleaner wrasse cleaning other fish.
Subadults have a blueish front half instead of a yellow front half.
Juveniles are black and purple.