What is this Acan doing?
 

Hi all, I have this Acan coral that I can’t for the life of me get to open. I’ve checked all the parameters and nothing jumps out at me as the reason why it stays closed. I’ve also tried various locations and combinations of lighting and flow. Anyway, I’m not expecting a magic answer on how to make it open, but today I looked at it and though the polyp was closed, it’s mouth was wide open. And I mean WIDE. Wider than I’ve ever seen a coral open it’s mouth. It seemed to be expelling a trail of brown slime, which I’ve seen many of mycorals do, but never with the mouth this wide open. I attached a picture of it. Is this normal? Might this gaping hole hold a clue as to why it won’t open? Thanks in advance.

Where did you position it in the tank? Acans tend to prefer lower light levels and do better at the bottom of the tank.

Right now it’s closer to the middle of the tank. I had it at the bottom out in the open where it got full light for a few days: no luck. I then moved it into the shadows of the rocks so it would get less light: still no luck. I moved it up off the sand bed because when it was all the way at the bottom it kept getting covered in sand by my Melanaurus Wrasse who likes to take mouthfuls of sand and then spit them out.
FYI: light is a Kessil AP700.