Some help? Unhappy toadstool.

[NoWaiAma]

Parems are fine. Minimal coral in this nano. He closes up daily but also expands to 3” and swells up polyps out.
Went to the lake for the weekend. Parems still good. Has this hole. Blew it no dust or detritus. Gets decent flow. Any ideas please ? I’ve caught my Scarlett on him a few times but that wouldn’t explain this. Thank you.

 

[Reeferdood]

It could be splitting, it is normal for them to retract their polyps for extended periods as well.

 

[NoWaiAma]

Today , the hole looks different from the pictures I’ve seen of splitting Guess all I can do is watch

 

[Super Fly]

same thing happened to my Devil's Hand (same family) few months ago, with a hermit crab by the hole. Only saw the hole during evening when coral was closed. After several days (maybe a week?) hole was gone, coral didn't split and it's been fine with no more hole. Have no idea what it was doing but it's been always healthy and continues to be today.