High Quality Content by WIKIPEDIA articles! Xenia is a genus of photosynthetic soft marine coral resembling a mushroom, with "arms" coming out from the top that end in many-fingered "hands". IT is unique among corals because of its ability to use its "hands" to "pulse" or push water away from the colony in a constant, grabbing motion. THis action, is unique to the Xenia and was once thought to be used to catch ambient plankton, is now thought to be used for respiration. IT propagates well with marginal care and is very suitable for beginning reef aquarium hobbyists. SAlly Lightfoot Crabs may clip arms from a Xenia causing it to emit a mucus. THis mucus will very likely induce a bacterial feeding frenzy that will kill the Xenia.