Leave it in there man...lol... if its the one you got from me, that was a split that healed into that crevice. Its gonna be hard to get it out of there in one piece. If I were you. I would place the anemone somewhere you know it wont be comfortable, try placing the rock upside down, or under direct light...the anemone will move away from the light if its too intense, or move right side up if you flip the rock upside down. Hope that helps.