Something's eating my toadstool

[pomoev]

Hi.
The coral looks healthy during the day, but I just noticed some holes in it.
What could it be?

 

[ProfessorAronnax]

What fish are in your tank? What inverts? See any pests around?

 

[pomoev]

Sorry for this little info provided.

Fish:
McCosker's wrasse,
Ocellaris Clownfish,
Azure damsel.

Inverts: turbosnails, candy pistol shrimp, bunch of brittle starfish.
I also got a couple of berghia nudibranchs a few weeks ago.

Last night I was looking around with a flashlight, didn't notice anything suspicious.

 

[pomoev]

I noticed this morning that when the coral fully extends it's kinda rubbing itself against a bivalve sitting not far.
I hope it's just a physical rubbing impact, not that the mollusk is eating the coral.

P.S. Found this article about bivalves and corals: https://reefbuilders.com/2019/02/05/boring-bivalves-are-eating-corals-from-the-inside/#

 

[ProfessorAronnax]

I would suspect that rubbing that has something to do with it. Maybe try moving it and observe further? Always keep an eye out for pests!

 

[DannyBCorals]

I see some aiptasia next to it. They usually sting corals and it results in the damage you see on the mushroom.