if they are palythoas then they are corals, and good ones. I had a few on my rock and they spread so quickly it was crazy lol.
In fact they spread so fast and so much I plan on fragging mine out to get them down a bit.
I;d wait for another opinion on them being paly's though, my speciality isnt identification really, just looks exactly like what I have.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.