Ufo scoly

[Aquaticsole]

Can someone please tell me why my scoly is showing skeleton and releasing its filliments continously? Just a little at a time but has been all day, parameters are,
P.H=8.0
KH/Alk= 9.8
Po4= 0
No3=0.5
Cal 440
Mag 1380
Amonia 0
It looked amazing yesterday, plump happy bright, it still has its color but i am at a loss, i did see a hawk fish trying too steal food feom it is all, can an annoying fish cause this?

 

[Retro Reefer]

How old is the tank? Better picture? Lighting? Flow? I would get your nutrients up and your Alk down to start with.