A crab barely 1.5 cm (0.6 in) across, its pale shell patterned in a fine dark mosaic, and a small anemone held in each claw like a pair of gloves. The claws are too small to fight with and are never used for it: they exist to carry the weapon, and the crab waves the anemones at anything that comes close.
The anemone is usually Triactis producta, and the arrangement is one-sided. The crab wipes its anemones across the substrate and eats what sticks to them, so the anemone loses part of every meal and stays small. Deprived of one, a crab will tear the remaining anemone in half and wait for both pieces to regrow - which is where the aquarium trade's supply comes from. Females carry eggs under the abdomen and continue to hold the anemones throughout. Look under stones in shallow rubble at night; the crab itself is almost invisible, but the two pale dots it holds up are not.
- a small anemone gripped in each claw, held out in front
- pale shell with a fine dark mosaic pattern
- walks with the claws raised, never using them to pinch
- width up to 1.5 cm
