Long tentacle plate coral

[tweetysox]

Hi, I have a question regarding my plate coral. It used to open up beautifully everyday, for 3 days now it has been closed with no signs of it opening...is it dying? my water perams are good, the only thing i added new was an anemone which is on the opposite end of the tank. Could he just be P.O'd due to me putting the anemone in the tank? Please help.