Blue-cheeked Butterflyfish

Snapshot: The Bluecheek Butterflyfish sports a bright yellow body with thin red / orange vertical lines. Unlike most other butterflyfish, it has no eye bar, just a grey patch behind its eyes.
 
Other tidbits: Can grow up to 23cm or so. Native to the Red Sea and the Gulf of Aden. This stunner is highly prized by marine aquarists for its beauty.
 
Bare bones must know: Live-rock fish only system, or fish only system. Top notch water quality. Too many active swimmers, like wrasses, can stress it.