Zoanthids are dying?

[Matrioshka18]

Hello! I have had this zoanthid colony for 7 months. Not sure how to describe this but some purple looking wire is covering the corals. It has been slowly growing around the coral for the past month.

 

I tried removing some yesterday and many polyps are not opening. Not sure if I did damage to it. I gently used some tweezers and pulled the purple. It was hard like weeds.

 

Salt:

Before, I was using AccuraSea1 by 2 little fishes and I was changing 2 gallon of water every week. I changed to red sea coral pro 2 weeks ago and did a 3 gallon water change. 

 

The tank is the evo 13.5 gallon. 

 

Colony was much fuller. I attached a before picture where clown got in the way. In the after picture, much of the purple was removed and colony has shrunk. 

 

If anyone can let me know if this purple stuff is normal and can this coral recover with a few polys left, there are about 10. Thanks.

 

 

[RustyRocket]

If you've tried most things a peroxide dip would be very useful. but make sure all the zoas are closed up first. Theres plenty of resources online for instructions on a peroxide dip.