Pulsing Xenia is my favorite soft coral. Everyone loves to watch the individual polyps open and close independently of each other. Although they can spread to weed-like proportions, I have come to rely on them for indications of the tank's condition. If all is well, they look happy, and conversely when they look droopy or mangled, something is out of whack. They are truly my 'Tank Barometer.' Since they grow upward toward light, placing them up high will control their spreading.