Do you know if it's photosynthetic or non-photosynthetic? My phtosynthetic one closes up for several days every couple of months. Not sure why it does this. On one occasion it closed up for a week and a bit of algae started to grow on the branches, it had to brush it off with my hand. A day or two later it opened up and looked great. I've had the coral for 4+ years now. If it's non-phytosynthetic you might have a really hard time keeping it alive, unless your dosing phyto or some other specialized food. The non-photos sometimes close up and just wither away, unfortunately.