YYCGUY's Red Sea 500S

[yycguy]

Question about Zoas ?
I have about 6 colonies of Zoas in my mixed reef. Last we one of the colonies that I have had for at least three years of 50 plus heads just closed up pretty well over night and died! There is another smaller colony (doing very well) right next to them and the only other thing next is a Monti Cap that has been there for over a year or two as well. Any ideas what happened?