Zoanthids receeding, flatworms?

[footbag]

I have noticed my zoanthids receeding over the past month. None of them had moved and there haven't been any changes in my tank. I did add some rock at around the same time I noticed this. I am thinking that it might be flatworms, but I havent noticed any. All of my params are fine, and I'm getting nervous because I don't know whats wrong. My clove polyps which I used to have a ton of also died off. I looked at their stalks for brown spots, but didn't see anything.
Would I be able to remove a peice of rock and treat it in a dip to see if worms drop off of it? Can anyone think of what else it could be?

 

[algaepad]

Does anybody have a picture of these sundial snails? I too am having problems keeping zoo's and everything else in my tank is doing fine. Now that I have read the last post about these snails I am thinking I might have them. I have what seems to be hundreds of little snails that group together on the bottom sides of the tank. They are maybe 4-5mm across, teeny things.
If this is what I have, how do you get rid of them? Hand pick them out?
Thanks in advance!

 

[innsmouth]

https://forums.saltwaterfish.com/t/130468/what-eats-zoos

 

[thomas712]

Have you noticed any tiny starfish on and around them? Look at night or in the morning.

 

[bang guy]

Sounds like chemical warefare to me. Any other softies "upstream" from the Zoa's?

 

[footbag]

Would a colt or leather coral be causing chemical warfare?

 

[bang guy]

Yep. Could be. That doesn't mean it's happening but I've seen it before. Can you frag the zoo colony and set one frag somewhere else?
GAC can help too.

 

[footbag]

I'll do that. I will pull out a frag of the most noticibly receeding zoa and place it into my nano.

 

[newty]

another possibility is some sort of pods are attacking the zoos. it happened to a buddy of mine, whose pods (i do not know which) had multiplied to the point that there was no other vegetative matter and became slightly carnivorous. he isolated the corals, did 3 freshwater dips, left it in the quarantine tank, got a mandarin, and put it back in 3-4 weeks later. now, this is what he was told by our excellent LFS, so...
also, i recall reading something authored by anthony calfo on this subject on the net somewhere. perhaps do a search?
newty.