Originally Posted by fishieness
judging by the pic, either you have 20000K halides or that pic is taked with just the actinics on. And since his feeder tenticals are out im guessing that just your actinics are on? They will retract slightly at night. I have never seen the skeleton on mine however. Maybe that is why it sometimes looks fine and then bad other times. if the lights are tunred off, just the actinics are on, or the lights are jsut turned on, then the brain will look a lot smaller. however, in a healthy brain coral, you shouldnt see the skeleton. My guess is that is it on its way. or not oding well in your tank, or maybe it just wasnt doing well at the LFS.
please post your water paramaters
lighting and schedual
how long you have had it and how long this has been going on
and what other live stock you have including inverts, shrimps, fish, surrounding corals.
I agree with all of this, I also want to add in, placement of the coral plays a important role! I know a lady who had a issue with her open brain not looking pretty, but when she moved it to a different spot, it looked a lot better and was rebuilding back. Good Luck! :happyfish