zoas not opening

[reginalddecker]

I have this colony and not all of them are opening. It has been in the tank for about 4 months and originally all of them would open.
I dont know if you can tellby the picture but it appears as if there is a white crust forming on the outside of the zoa that is preventing it from opening. Do I have a predator? If so how can I fix the problem. Thank you
Reggie

 

[lfduty]

I'm in love with that zoa. I see it. It looks to me to be just sand iv seen it do that on some of my zoa's but you can do a FW dip if you think its a problem. I don't think its a predator it may be a fungus or a sponge. It's a little hard to tell.
good luck with it and hope it's not some thing bad.
I will have some one come over and look at it he is a LFS owner and i will link this thread in my reef clud forum to.

 

[aquaman2000]

Reggie,

There can be many reasons why a zoanthid will not open. The first things to think about is chemistry followed by lighting, flow dynamics and tank mates. It could be as simple as the presents of algae and a herbivores fish is eating it and irritating the Zoa’s. From the pic you posted, it appears that only a few polyps are not opening. It is also not uncommon for some polyps to jump and let the currant move them elsewhere to start a new colony. I have also seen some polyps just close up and die without effecting the rest of the colony. You will also want to inspect the colony at night with a flashlight to see if there are any Zoa eating nudibranchs. Another possibility could be that the affected polyps are being stung by a neighboring coral. And then finally, sometimes they just close for awhile and will reopen and be fine. Check and maintain your water, look for nudis and try to give us a little more in put to help you solve your problem