The Pyramid Butterflyfish (Hemitaurichthys polylepis) is a species of butterflyfish in the genus Hemitaurichthys.
The butterflyfish can grow up to 18cm in length. The Pyramid Butterflyfish is usually seen in depths between 3 m and 60 m in outer reef areas close to drop-offs. It often forms large shoals containing hundreds of individuals all swimming high in the water column feeding on plankton.

This species occurs in tropical marine waters of the Eastern Indian Ocean and Western and Central Pacific, from South-east Asia, Christmas Island and Coco-Keeling Atoll, north to Japan, south to Australia and east to the Hawaiian and Pitcairn Islands. In Australia it is known from the north-western coast of Western Australia, the Great Barrier Reef, Queensland and northern New South Wales.

This butterflyfish family contains a colorful collection of fishes with diverse body patterns. This butterflyfish bears a white pyramid-shaped patch on each side. As it grows its head changes color form yellow to brown. (text source: Wikipedia)

Pictures: Misool Islands, Raja Ampat, Papua, Indonesia by Sami Salmenkivi