I bought a frag o' xenia about 2 weeks ago and it's really doing well. But I just noticed last night that between some of the xenia stalks and around the fringes of the "rock"(which is fingery), there is some yellow stuff, which I think is actually remaining stony coral.
I can't see any polyps clearly, but there are some tiny uniform bumps on it, I was thinking maybe yellow Porites.
Anyone know?