Chaetodon striatus

Actinopterygii: The Actinopterygii, or ray-finned fishes, constitute a class or subclass of the bony fishes. The ray-finned fishes are so called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines ("rays"), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii. In terms of numbers, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. (Wikipedia)

Tropical: The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at 23° 26' 16" (or 23.4378°) N and the Tropic of Capricorn in the southern hemisphere at 23° 26' 16" (or 23.4378°) S; these latitudes correspond to the axial tilt of the Earth. (Wikipedia)