Decorator Crabs

Majoidae superfamily

Maximum Size:

5 in (12.5 cm)



Typical depth:

0–660 ft (0–200 m)


Decorator crabs are a subset of spider crabs (of the crustacean superfamily Majoidea) that attach plants and non-moving animals to their shells as camouflage or to ward off predators if the decorations are noxious. Estimates suggest that 75% of the crabs within this group undertake some form of decorating behavior. The decorating is possible thanks to the rows of tiny hook-like structures on the crab’s carapace and legs.


Grouper, triggerfish and grunts.

Did you know?

Crab shells do not grow. So as the animal gets bigger, it is forced to molt, which involves shedding its shell in the process. Decorator crabs carefully remove the decorations from their old shells to reuse on their new ones.