The Oval Butterflyfish, Red-finned Butterflyfish or redfin butterflyfish (Chaetodon lunulatus) is a species of butterflyfish (family Chaetodontidae). It is found in the Pacific Ocean from Eastern Indonesia to the Hawaiian islands. This is one species of a closely related group which includes the Blacktail butterflyfish which is found in the Red Sea and Gulf of Aden and the Melon butterflyfish which is found in the Indian Ocean.