How do Acans react to soft coral chemical warfare?

[Koralliono]

All of my acans' tissue has been retracted for the past two days - all acans at the same time and only the acans - without any change in lighting or water parameters and I am wondering if it could be due to soft coral chemical warfare. Does anyone have any thoughts or references on the subject? Any help greatly appreciated!

 

[Zero Nitrates]

Could be chemical warfare.

What else is in the tank? Do you run carbon?

 

[Koralliono]

Variety of LPS and softies.
Naso tang, sailfin tang, potter's angel, rabbit, tricolor wrasse, single clown, lyretail anthias
Yes I run carbon. Carbon+GFO and nothing else.

 

[Zero Nitrates]

My guess is a fish is nipping at them