I think more importantly is that this particular goniopora coral is on its deathbed. These corals are particularly more difficult to care for than most corals. Was the coral tissue receding like this when you purchased it?
No He was given to me about a year ago. He was all fine. All the water parameters are fine everything else is blooming and growing but him. The previous owner had him for about 4 years.thanks for the quick reply.
Since your water levels are pretty decent, I would look to feeding. What kind of food have your been feeding your Goni? IME they should be treated more like an NPS coral than an LPS in regards to target feeding etc.