Whats the matter with this zoa?

This is my first "what the matter with my coral" post. I have a 70g tank that has been running for a year. A few months ago I added a torch and two zoa frags. I have one green zoa and one pink. Since I added the green zoa it has about doubled in heads. The torch is also looking good IMO (but I dont really know what to look for). However, the pink zoa has not really grown and now is starting to look really bad. It looks like the heads are turning white and dieing off. Here are some picks to help:



Greeen zoa







Torch







Pink zoa