To the other corals... possibly fish, they were all tightly hunkered down amidst the event. I am about 90% on it being a sexual event... and here's why: I turned the lights on one morning, to find that the tank was a thick white-out. Like slightly watered down milk. All corals were retracted, some already showing tissue damage/death. All xenia were "deflated" (for lack of a better word). Once all the coral got situated again, all the Xenia appeared to be gone (yay!). Not long after, baby xenia began sprouting up everywhere... in the middle of zoa colonies, on/around all manner of coral, etc. It sucked. Hard...
Thats a nightmare! I'll never be able to look at a xenia the same again...dirty little corals.