Apologies for not knowing what this is called, I inherited the tank!
Yesterday the fuses in our kitchen blew and everything in the tank went off, this coral/anemone went totally flat and shrivelled up to the point that I could see it's foot(?) I also spotted a line of brown stuff (poo?) coming out of the centre at one point. It did eventually start perking up and today it was back to full size. I've just popped into the kitchen again and noticed it has gone all flat and sad looking.
Everything else is looking fine, I do know when the lights start getting dim everything seems to shrink down as I watched that happen 2 or 3 nights ago but everything else is still awake as it were.
Photos 1 & 2 show it at it's norm
3&4 are yesterday when it really shrank down
5&6 are tonight, it is bottom left in photo 6