Singular Bannerfish (Heniochus singularius) シマハタタテダイ
A juvenile Singular Bannerfish has a prominent white spine on the dorsal fin. There are three white bars on the Singular Bannerfish, one across the snout, one behind the eye and the third goes from the spine to the tip of the anal fin. If the middle white bar goes to the spine, you are looking at a Masked Bannerfish. Amami
An adult Singular Bannerfish can grow to 30 cm. Here you can see it has changed a bit from the juvenile. The third and last white bar has a lot of black in it through the body. It still goes from the tip of the spine to the tip of the anal fin. They are often seen by themselves. They do sometimes school with other fish including other different types of Bannerfish. Amami