Zoa not fully opening until I fragged it?

[homebrewdude]

I had a small rock with some zoa on it.
I had this next to some other small rocks, as expected they grew and spread to the other rocks.
Then they started to not open all of the way. They were open but the long parts were not extended.
So I pulled the rocks apart and put them in separate areas of the tank.
I also cut some off the original and glued them to new rock.

They are all opened fine now EXCEPT the original colony.
Any thoughts or something I should look for on the main colony?

 

[ReefFiend]

Pictures of the problem polyps would probably help out....

 

[edwing206]

Nudibranches.
Anything crawling on them?

 

[msman825]

Pest perhaps. A pic would give us something to go by

 

[homebrewdude]

Here are some photos.
They are located next to each other in the tank

Image weeks before the frag - on the right side

After frag

Frag