I have an Octospawn that's is about mid level in my 40 gallon IM with moderate flow. It's a 2-head frag, and one of the heads has completely retracted without a single trace. The other head looks like its not not far away from the same fate. Now here is the good news.... All of my other corals are thriving (hammers, torches, frogspawn, etc..), and my parameters are in check. Any advice would help.... Thanks in advance!