Anemone Decorator Crab

Cyclocoeloma tuberculatum

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Majidae
Genus: Cyclocoeloma
Species: Cyclocoeloma tuberculatum

The anemone decorator crab (Cyclocoeloma tuberculatum) is a spider crab that plants small living anemones all over its shell, turning itself into a walking garden. Beneath its decorations the carapace is rounded and knobbly, but usually only the crab's legs and eyes give it away.

It typically reaches a carapace width of around 3-5 cm. The crab cultivates its anemones by attaching them with hooked setae, and the stinging tentacles help deter fish and octopus. It feeds at night, picking at algae, detritus and small invertebrates, and if it moves home it can transfer its anemones too.

In the Philippines the anemone decorator crab is a favourite muck-diving find on sand and rubble slopes, most often encountered on night dives when it wanders slowly across the bottom looking like a drifting clump of anemones.

Photo: Dan Schofield, CC BY 4.0, via iNaturalist