Also known as Brachyura Crab, Decorator Crab, Prickly Spider Crab, Soft Coral Spider Crab, Spider Crab, Spiny Spider Crab, True Crab.
Found camouflaged with debris, rubbish and weed etc. on mud and sandy areas, close to soft corals and sponges over coral and rocky reefs.
They feed nocturnally on plankton.
Length - 4cm
Depth - 2-15m
Widespread Indo-West Pacific
Brachyura crabs are considered true crabs, they have a short abdomen, 4 walking legs and a pair of clawed arms at the front.
Many thousands of species live worldwide in sea water, fresh water and on land. Ref: https://en.wikipedia.org/wiki/Achaeus_spinosus