Decora Goby

Snapshot: Also known as the Purple Firefish. Its body pops with yellow and white, blending into deep purple shades that start at the head and fade into maroon-tipped fins for a bold finish.
 
Other tidbits: Can grow up to 9cm or so. Distributed throughout the East Indian Ocean, West Indian Ocean, Australia, The Red Sea, and Indonesia.
 
Bare bones must know: Live-rock fish-only system or reef aquarium. Thick, sandy substrate required.