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!


Here's how they look now



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

[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

and Symbiodinium or Zooxanthella which is also something they are made up of:
Symbiodinium - Wikipedia, the free encyclopedia

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

[larryandlaura]

Great read!