Could it be the skimmer?

[MizTanks]

Ever since I placed my skimmer back in my tank, all the zoas near it are dying off. I mean all of them!!
On the right hand side you can see where the skimmer is. See where all the zoas are receding? It's terrible!
http://img.tapatalk.com/d/12/10/31/eba5ydeh.jpg

Here's how they look now

http://img.tapatalk.com/d/12/10/31/ade4eha4.jpg

Here's what they used to look like about 3-4 months ago.

http://img.tapatalk.com/d/12/10/31/yqydyju3.jpg

[larryandlaura]

Weird, is something bothering them like a crab or copepod?

[AZDesertRat]

I believe zoanthids actually prefer less than pristine water conditions like many soft corals. I find when I ignore my systems and get lazy with water changes the softies do better but the stony corals start looking stressed. On the flip side when I keep up with skimming, water changes and media changes like a half does of GFO and some GAC the stony corals perk up but the softies recede.
Just one of the drawbacks of a mixed system I guess.

[MizTanks]

The skimmer is only skimming the surface water. I'm only doing 1x bi-weekly WC at 6g per.

Could a few Digitate Hydroids be the cause?

[AZDesertRat]

The skimmer is removing or reducing the organics in the water which is what the zoanthids are feeding on.

Reserach Cnidarians, which is what zoanthids actually are:
Cnidaria - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Cnidarians)

and Symbiodinium or Zooxanthella which is also something they are made up of:
Symbiodinium - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Zooxanthella)

In the Cnidarian artice it talks about the consumption of organics etc.

[larryandlaura]

Great read!