Zoanthids

[Rybak]

Good afternoon! I’d like your help evaluating my zoanthid corals. Some of them look shrunken and have elongated stalks, even though they’re positioned closer to the light source. My aquarium is a Biocube 14. The white light spectrum is set at 65%, and the blue spectrum at 95%.

My water parameters are as follows: calcium 420, magnesium 1350, and I try to keep alkalinity around 8–8.3 dKH. The pH is 7.8 at night and 8.1 during the day. I dose Aquavitro Fuel at 2.5 ml every three days and add 12 drops of Coral Amino every other day.

I even sent my water to a laboratory to check for any harmful contaminants, but nothing was found. My phosphates are between 0.12–0.15, and nitrates are 9.5.

I also have a bubble tip anemone and a Montipora gigantea in the tank. The Montipora is growing new polyps, and the anemone hasn’t moved from its spot and seems perfectly healthy.

I just can’t figure out what’s wrong with my zoanthids. Do you have any ideas?

 

[fandaga]

Since it’s a small tank, I would just do several medium to large water changes spaced out over a week. Hopefully the salt that you use is about the same alk and calcium that you currently have.

 

[Rybak]

Since it’s a small tank, I would just do several medium to large water changes spaced out over a week. Hopefully the salt that you use is about the same alk and calcium that you currently have.

I use instant ocean, but always increase calcium and magnesium in the change water with reef fusion 1 and reef fusion 2

 

[fandaga]

So one possibility is that your iodine levels might have bottomed out. I check mine periodically with either the method posted on reef2reef or by ICP. But it could easily be something else that’s bothering them. At least the water change should fix either iodine or the “something else”.

Another issue might be a fish or invert that is annoying them…

 

[Rybak]

A month ago, I did an ATI test, and my iodine levels were at 33.17 µg/L. I also did large water changes and even added carbon, but it didn't help.

 

[qrri4912]

A month ago, I did an ATI test, and my iodine levels were at 33.17 µg/L. I also did large water changes and even added carbon, but it didn't help.

Did you manage to solve the zoanthus problem?