Halp! My zoanthids are withering away.

[SptfireXIV]

Something is decimating my zoanthid population and I can't for the life of me figure out what it is. At first I thought it was sundial snails, but I think the majority of the snails I've been removing are collonista

Pics:
From this:

To this in about 2 months time:

Thats the worst case of it, but all of my zoanthids have been suffering the same fate. Its really depressing to watch them wither away like this.

The only fish that I have that may be a culprit is a Cherub Angel, but I watch him like a hawk and have never seen him nip at anything but my gorgonian when it sheds its slime coating (ALL my fish have this behavior though). I also have a sally lightfoot crab, but I've also never seen it bother the zoanthids.

Edit: Heres some more "after" shots that show the different types of damage done.
These are all spaced out and most of the "mat" between the polyps has disappeared.

Same with these:

The polyps constantly look like something has eaten part of the skirt. They also have trouble closing after this happens.

Edit: I should add that I dipped all of the zoanthid colonies that I could in an Iodine dip and nothing came off of them but a few more snails and a couple of pods (and potentially a micro sized bristle worm).

 

[Bebo77]

i would move them to a different spot in your tank, see if that helps...

 

[Strega]

I think Bebo just about covered it except that Zoos are photocynthetic. They need light. I don't know what kind of light you are running but maybe if you move them higher in the tank they get the light they require. P.S . Magnesium is ultra important for Polyp expansion in soft corals. So it would be wise to get a test kit for that and all the other major ones like Bebo listed.

 

[SptfireXIV]

I can try moving them around, but each colony is in a different part of the tank already.

I doubt its lighting, the tank is set up for SPS. Its 36x24x20 and has a 6x39 watt tek fixture over it. In fact I bleached many of the zoanthids I have when I first got it because I didn't realize the lights were that bright.

 

[killingseed]

the first images look just like what a happen to my brothers zoa's which i now have in my tanks.

his problem was a mix of a few things. sality was one he wasnt keeping up with evap water and just letting it ride till he could get the water for replacement. BAD! very bad a simple ATO can take care of that error. second, flow, when he didnt have enough water he would turn off the main pump, which provided most his flow. the 3rd and lost thing is light he killed his timer so the light where not coming on and off or a good 10 hours or so.


once placed in my tank the skirt have opened the colors are back and they are reproducing again. but over all any one of things can cause issues and should be looked at.

 

[SptfireXIV]

Hmmmmm. Well, maybe its not something eating my zoanthids then like I thought it was. I'll try upping my water change regiment, but pretty much all the things you listed I've got covered. Using an ATO, my main T5s are on for 8 hours a day and I've got like 37x turnover. I'll try moving them around a bit though. Thanks!


Whats really odd though is that they're still reproducing quickly, but then they seem to die-off for a while, then they come back strong again. Its the craziest thing.

 

[edwing206]

That's what happened when my salinity got way high. When I brought it down they were fine.

 

[ficklefins]

I would agree with the comments above. From how your zoas/palys are reacting it really looks like something with your water. I would test, find someone else to test, and ask a LFS to test. This way you will find what may be causing this issue. I had the same thing happen in my tank when I introduced equipment that still had some bleach residue on it. NO Good!

At first, when zoas are being harassed by pests only those zoas affected will show signs of stress. If all, or a majority, of your zoas look stressed, or bleached, then it may be safe to assume that it is something in the water column (especially if this happened overnight).

 

[ClownNut]

check your ALK and Ca. last time that happened is my Ca at 500.

 

[SptfireXIV]

Alright, will do. I'll test everything tonight. Thanks guys!

 

[TWallace]

I don't think it's a predator either. If it was a predator, you'd have some zoanthids closed up fully, while others looked fine. In your tank, it looks like they're all partially closed to the same extent, roughly. To me that says something is irritating them all the same amount. Predators don't do that, but water quality does.

 

[650-IS350]

They look REALLY stressed... its most likely your Alk/pH ... do you have temp spikes? another cause.... I've had zoos do that before when I did not know my pH was fluctuating and Alk was low.. lost some zoos... now with a more stable system zoos are doing a lot better...