Very special thanks for thr first photo of a living Chaetodon flavocoronatus to LemonTeaYK :-)
Chaetodon flavocoronatus also known as the Yellow-crowned Butterflyfish is endemic to the Marianas Archipelago.
Only three species of shallow-water reef fish are known to be endemic to the Mariana Islands the Yellow-crowned Butterflyfish is one of it.
It is occasionally seen in the aquarium trade. Little is known about its biology.
Butterflyfish are not recommended for reefs as they will pick at or eat a wide variety of corals, fan worms, and other invertebrates. Most Butterflyfish are known to pick at Aiptaisia, a parasitic anemone.