The eastern triangle butterflyfish is found in the central Indo-Pacific region, from the Cocos Islands and Indonesia in the eastern Indian Ocean to the Fiji and Tonga islands, north to southern Japan, and south to New Caledonia and the New South Wales region in Australia.

The eastern triangle butterflyfish is listed as many other marine species within The IUCN Red List of threatened species. The eastern triangle butterflyfish appears in the IUCN Red List since 2010 within the category Least Concern !

Be careful not to confuse the eastern triangle butterflyfish with two other species of butterflyfish looking similar, the triangle butterflyfish (Chaetodon triangulum) you can find in Madagascar, in Seychelles, in Mautitius island as well as in Chagos archipelago and the triangulate butterflyfish (Chaetodon trifascialis).