I have a 2 and a half year old 65 gallon softy/LPS tank, and over the last few days I've noticed that one of my 2 Xenia colony's has been rapidly dying off. In the last week about one-third of the colony has been completely killed and is now laying in pieces on the sandbed, another third is shriveled and on the brink of death, and only about one-third is still healthy. The only change to the tank in the last 6 months was a coral shipment I got right after Black Friday. The order was delayed in shipping by a full day and so 2 of the corals were melting away when I got them and were dead within a couple of days, where I then removed them from the tank. Due to the fact that all the corals in the shipment were cold and on the brink of death when I got them, I did not dip them immediately and instead let them recover in the tank for a few days before pulling them and treating them with CoralMD.
I don't think it's parameter-related. I have another pulsing xenia in the tank and aside from a couple of stalks that were killed by an encroaching Leptastrea, the colony is in good health. The same goes for all my other softy and LPS corals; they've never looked better. The issue appears to be localized to the rock the Xenia is on. On further inspection, there's weird brownish-white spots on the bases of the dying clumps that appear to almost be deformed. I've attached pictures with white light to see if anyone can ID and suggest what to do. If you need any more info to help I can definitely provide it. I just want to stop whatever this is before it starts killing more expensive things like my Zoa garden or my Euphyllia.
I don't think it's parameter-related. I have another pulsing xenia in the tank and aside from a couple of stalks that were killed by an encroaching Leptastrea, the colony is in good health. The same goes for all my other softy and LPS corals; they've never looked better. The issue appears to be localized to the rock the Xenia is on. On further inspection, there's weird brownish-white spots on the bases of the dying clumps that appear to almost be deformed. I've attached pictures with white light to see if anyone can ID and suggest what to do. If you need any more info to help I can definitely provide it. I just want to stop whatever this is before it starts killing more expensive things like my Zoa garden or my Euphyllia.