Glove polyb Not opening well

[Mohammad.ki]

Hello

Pleas can you tell me why this coral not opening well it was in my aquarium for more than 9 months and it was very happy and when i get it it was small they grow in my aquarium now it look like this and no problem in my water all other corals helthy only this one from two weeks like this - what should i do for it ?? Any help

 

[Macbalacano]

Please post your water parameters

How is the flow? In my experience, they seem to like low/moderate flow.

Any livestock in the tank that could be bothering them?

Any recent changes to the tank?