Fish ID: Pyramid Butterflyfish

Butterflyfish pyramid butterflyfish hemitaurichthys polylepis thl pair
Family Butterflyfish (CHAETODONTIDAE)
species Hemitaurichthys polylepis
size Up to 14cm
locality Outer reefs
behaviour Usually in large schools
range Eastern Indian Ocean and Pacific

Looks like a solid white triangle on a yellow body. Face is brown and tail is white.