Xanthid crabs superficially resemble swimming crabs (see later) but note that the hind legs are of the clinging type in Xanthids not paddle shaped. Over recent years there is one species of crab which has become much more commonly encountered than in the past. This is due to the increased amount of pulsing Xenia spp. imported for the aquarium trade. The white pearlescent Xenia crab is often found ensconced in even surprisingly small colonies of Xenia soft coral. The nature of the beast is difficult to ascertain. Early encounters suggested that the crab was a harmless commensal species perhaps living off the mucus of the coral. Due to the increased volume of encounters with this animal a different story seems to be emerging. That the pulse coral is bothered by the presence of the crab is certain. I have witnessed small colonies shrink in size due to its presence. It could be that larger colonies are not bothered unduly by its behaviour as the disturbance will be shared by most of the colony rather than a small area as in the case of smaller pieces. However, there are reliable reports of the crab consuming the Xenia itself often after the colony has become damaged in some way. For this reason I must recommend removal of this undoubtedly beautiful creature.
