King Angelfish

Snapshot: Adults flaunt a deep midnight blue body, highlighted by a bold white stripe that drops down from the dorsal fin, stopping just short of the pelvic fin. That dorsal fin is edged in a slick yellow trim, matching the bright yellow caudal and pectoral fins. Juveniles rock more of a fiery orange coat with one standout white stripe and a bunch of cool blue ones to match.
 
Other tidbits: Can grow up to 36cm or so. Distributed throughout the tropical Eastern Pacific Ocean from the Sea of Cortez to Ecuador and Peru.
 
Bare bones must know: Live-rock fish-only system, fish-only system, or reef aquarium with care.