Yellow Watchman Goby

Snapshot: Also known as the Yellow Prawn Goby. It has frog-like eyes, perpetually frowning lips, and a shimmering yellow hue adorned with tiny blue dots. As they mature, their vibrant yellow can fade into a more subdued shade of white or gray.
 
Other tidbits: Can grow up to 7.5cm or so. Range extends from East Africa through the Indo-Pacific region, to Japan in the north and Australia in the south. It's the "Watchman" in its name that steals the show, because this goby forms an unbeatable bond with shrimp.
 
Bare bones must know: Live-rock fish-only system, fish-only system, or reef aquarium. Thick, sandy substrate.