Losing my zoas?

[Maxxingout]

I have 2 sets of zoas that I bought over 1 month ago. They've been doing great and slowly growing in that time. Just recently I noticed that my 1 set has been slowly loosing heads. I tried taking a picture with my phone to see if anyone might see something? I tried doing research and noticed something that might resemble Spionid Worms or Hydroids? I'm not sure though so hopefully someone with more experience can help. The 2nd colony so far is doing good with no lose of polyps or even closing up.

Here's some pics:


a pic of the 2 colonies:


I still need to use a flashlight when lights are out to see if I notice anything.

 

[Relojdepeso]

Just look at them carefully during the day and look at your rocks to see if you see any Zoa eating nudibranches. Also check you parameters to see if they're in check.