Red Spotted Guard Crab

Trapezia tigrina

Carapace to 1.5 cm. Cream to pink with up to 150 bright red spots; six small-lobed teeth between eyes; lower claw edge smooth. Commensal with Acropora/Pocillopora branching corals. Use large claws to ward off coral predators. Distribution: Indo-Pacific, Japan and Hawaii.
Red Spotted Guard Crab - Trapezia tigrina in Pocillopora possibly damicornis or verrucosa coral. Fall,Geotagged,Indonesia,Red Spotted Guard Crab,Trapezia tigrina

Defense

Fun fact: The red spotted coral crab may be small, but animals should think twice before messing with it! It lives on and in coral, and will defend its home, using its claws to pinch and drive away predators who want to eat it or its coral. For example, when a crown-of-thorns sea star climbs on top of its coral, it will pinch at its tube feet. The pain forces the sea star to crawl away, defeated. Since the coral provides the crab with a safe place to live, and the crab protects it from predators, they live in a close, or symbiotic, relationship that is mutualistic—good for both of them.

References:

Some text fragments are auto parsed from Wikipedia.

http://eol.org/pages/318251/overview

Reef Creature Identification Tropical Pacific by Paul Humann and Ned Deloach.
Taxonomy
KingdomAnimalia
DivisionArthropoda
ClassMalacostraca
OrderDecapoda
FamilyTrapeziidae
GenusTrapezia
SpeciesTrapezia tigrina
Photographed in
Indonesia
Maldives