View Full Version : Zoanthid closed up. What is wrong?

06/03/2017, 10:23 PM
Zoanthid closed up. What is wrong?
I bought this 10" colony about 6 months ago and has been opening up until a month ago. I did a coral-RX dip and moved it to 10G tank for observation. I don't see any pox or nudibranches. I see a lot of sand like white specks or small snail eggs on the rock and the polyps that I could not swish off by turkey baster. It must be these white things that irritates the polyps. Are the pox? Dead snail eggs? What are they? How to get rid of them? They have been here not growing or moving ever since I found them. Or anything else I didn't notice?

Below are some pics that hopefully you experts can tell me what to do before the whole colony dies:









Here are the direct links to the 16MP version:


06/04/2017, 12:02 AM
There were vermitid snails which can bug corals. The white things look like feather dusters which won't hurt anything. Did you change lights, flow, or salt mix recently?

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06/04/2017, 09:54 AM
FWIW that starfish on the right in the first picture has been known to eat zoanthids before. (Asterina) I'd definitely remove that first and then check the colony at night with a flashlight for more starfish, nudibranchs, sundial snails etc. Another dip might be in order.

06/04/2017, 10:45 PM
The rock has been in a 65G tank since day 1 six months ago. Then since last month overnight, only 10% of polyps was opened. That was without any light, flow, or salt mix changes that I could remember. Then I moved it to a 10G for observation. That move did incurred light and flow change.

I will remove the Asterina (which I have seen it there since day 1) and I will see if I can find more critters that I don't see during day time.

I will update in a few days.


06/05/2017, 07:10 AM
FWIW that starfish on the right in the first picture has been known to eat zoanthids before. (Asterina) I'd definitely remove that first and then check the colony at night with a flashlight for more starfish, nudibranchs, sundial snails etc. Another dip might be in order.

This! I had this issue with my zoas.

If you have a large enough tank, a yellow coris wrasse would eat things that may be bugging your zoas that you possibly cannot see.

Razorback reef
06/11/2017, 02:05 AM
Have any other Zoas in there?

Razorback reef
06/11/2017, 08:46 AM
Also remember that maricultured colonies sometimes don't acclimate very well to a captive aquarium, they just slowly deteriorate over time.

You're always better off sticking to aquacultured frags.

06/11/2017, 03:11 PM
Have any other Zoas in there?

Yes, I do have other zoas in the tank. They are fine.


Razorback reef
06/11/2017, 10:31 PM
Then it isn't water chemistry, lighting, or pests.

Just isn't acclimating to captive conditions. Some of the new Polyps probably have so you'll likely end up with some frags at least.

06/11/2017, 10:59 PM
But I have had it for 6 months. Since day 1, the first 5 months it has been opened fully. I really have no clue how.

06/21/2017, 11:45 PM
Do you have a picture of it fully opened from before

06/21/2017, 11:56 PM
Ha, glad I did take a video of it months ago.
Here is a screen capture of the rock. It was not even fully opened:

http://www.beyondautomation.com/AImages/2017-06-21 22_55_02-VID_20170103_183424.mp4 - VLC media player.jpg

06/22/2017, 12:06 AM
Things have changed a bit in the past 2 weeks. I think I got rid of something under the rock. It was like an anemone or sponge or featherduster. I could not tell as the rock was out of water but I scraped it off then the polyps seemed to open up more slowly but one night my wife put couple supermarket clams in the tank and overnight the water got fouled up and since then the polyps all closed up. Now I put the rock back into my original DT and over the past 2 weeks, I see hints of polyps opening up....


I will see how it goes and I will update here.

06/25/2017, 10:36 AM


It seems like it is opening up more and more.

07/05/2017, 06:42 PM
Getting better by the day. I think it will be fully recovered: