Acropora mesenterial filaments stay extended without obvious reason

[biom]

Any thoughts on this? The filaments stay extended for long period (days) and only on coral's shaded parts. Could it be because they are starving? Find some info from here: https://www.reefs.com/blog/2011/07/23/when-corals-spill-their-guts/

NO3-0.1 mg/l
PO4- 0.017 mg/l
pH - 8.36
Ca - 400 mg/l
alk - 7 dkH
Mg - 1230 mg/l
K - 370 mg/l

Carbon dosing, Aminoacids and bacteria biweekly.

 

[71xlch]

I have read somewhere that something may be on its skin causing irritation.

 

[Reefvet]

Any thoughts on this? The filaments stay extended for long period (days) and only on coral's shaded parts. Could it be because they are starving?

There's nothing unusual about that. It's a typical feeding habit for night but it not limited to any particular time of the day.

It's common in corals that are on the vertical edge of a drop off and the bottom half isn't getting light.

It may also be protecting itself there. Your photos don't show what is adjacent to the coral on that side.

 

[biom]

I have read somewhere that something may be on its skin causing irritation.

Yes, could be, I've siphoned out thank bottom two days ago and there were lot of nasty stuff floating around.

There's nothing unusual about that. It's a typical feeding habit for night but it not limited to any particular time of the day.

It's common in corals that are on the vertical edge of a drop off and the bottom half isn't getting light.

It may also be protecting itself there. Your photos don't show what is adjacent to the coral on that side.

thank you, there are no SPS corals in close perimeter to that coral, but there are lot of Xenia around, another reason to start some bendazole treatment.

Picture of coral - it is the pink Acro close to the pump (sorry no better picture from today)

 

[Reefvet]

...there are no SPS corals in close perimeter to that coral, but there are lot of Xenia around..

Xenia could easily cause that coral to be defensive. Nothing will take over a tank faster. Particularly with good water parameters, which you clearly have.