Apparently it means he is dying, I believe this was nswered by Mr. X on another thread. :-(
Sorry to be the bearer of bad news.
Id keep an eye on him so he doesnt get under your sand and die there decomposing when he does finally die.
I had a red starfish and the exact same thing happened he lost each leg one by one. I finally removed him after he had one leg left. it was horrible. :-(
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.