Funny, thats 3 anenomies in 1 week ...2 Ritteri and now this Sabae going south. DO NOT WAIT TO REMOVE THE CORPSE when there is body peices beginning to deteriorate from the body, they are MOST TOXIC to the tank.
Actually, the first Ritteri, a green pruple tip at my LFS, the same place I just bought my last one; actually was attached to a rock and going thru self propigation, dividing. It looked just like this BUT, Never left the rocks, the foot was always secure. They grew to 3" and he sold them both.
The one I got, the same color and size, from the same shipment was doing the same thing, exploding itself, with hardly any tentacles reaching out, looking 'dead', however stayed attached to a pvc pipe the clowns are residing in, & it didnt eat. Went thru these contortions all the while my LFS said, "I still think its trying to divide, IF and when it does go riding the the water stream, its dead and DUMP IT"
The time it took to get to the stream riding really gave the toadstool corals heck. They were laying on the sides, but the heads were always with tentacles extended. The water parameters were in normal to best, until it began slowly dieing, overnight. I remebered to do the Clean up time right then and get rid of the corpse, + a 10% water change.
You are right to give your tank a week to fully recover, me the same thing.
All of that was 2 days a go, all is well now, the coarls are looking awesome and standing 'Tall". My LFS guy has a 100% gaurantee on everything he sells, this will be the first anenome Ive ever had to swap out. Next week.
I Hope this was some information to help.