I took this photo while diving off the Sunabe Seawall in Okinawa, Japan (East China Sea). It was moving fast for my novice 6mp camera and skill.
It looks like I fish I used to see on Guam called the Spotted Sweetlips, Plectorhinchus picus. I have a Micronesian fish book that says they can also be found around south Japan.
You can find it in the REEF FISH IDENTIFICATION Tropical Pacific book. Pretty sure it's the Many-spotted Sweetlips Plectorhinchus chaetodonoides, rather than the spotted aka dotted sweetlips P. picus.
REEF Headquarters | P.O. Box 370246 | 98300 Overseas Hwy | Key Largo, FL 33037 | USA Phone: 305-852-0030 | Fax: 305-852-0301 | email: REEFHQ@REEF.org