Filters plankton with feathery mouthparts from inside a soft coral colony.
A small porcelain crab, the carapace about 1 cm and rarely over 1.5 cm, translucent white to pale pink and marked with fine red or purple-brown lines and blotches, on long thin walking legs. Like all porcelain crabs it is not a true crab: only three pairs of walking legs are visible, the fourth being reduced and folded away out of sight, and the abdomen is tucked flat beneath the body. On the same corals it is separated from the candy crab at a glance — that animal is spiny, decorated with the host’s own polyps and carries elongate spines down the back, while this one is smooth, flat and undecorated. Within Lissoporcellana the species are told apart on the spines of the claws and the front margin of the shell, so a field photograph often supports the genus and no more.
It lives on Dendronephthya and related soft corals, and also turns up on gorgonians and black coral, sitting down among the stalks near the base of the colony rather than out on the polyp heads. The host is the way to find it: the colonies worth checking are the same ones that hold the candy crab, and a colony inspected for one fairly often produces the other. It feeds by unfolding a pair of long feathery mouthparts and sweeping them through the current to strain plankton, a slow rhythmic action that is the most useful thing to watch for and the frame worth having.
Legs are shed readily under handling or stress, which is where the name porcelain comes from; they regrow over subsequent moults. Pairs on one colony are common. Recorded from about 5 to 30 m, which is largely the range over which divers and Dendronephthya overlap.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
