Exposed skeleton on goniopora colony

[KonradTO]

Hi all,
I recently got myself a beautiful goniopora colony. It is always open and "fluffy" and seems also reacting to feeding. I noticed that there is some exposed skeleton when it closes up at night. It seems populated by sponges and other stuff. Do you think it will keep receding or I can leave it like this without fragging? I don't have the proper tools and it seems quite difficult to frag. Moreover it is a beautiful colony I don't want to risk it if it is not totally necessary.

 

[blaxsun]

If the rest of the coral is fine, I'd be inclined to just leave it and keep a periodic eye on that spot.