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zoas not opening after 3 weeks


dave w

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(edited)

At the end of June I got several hundred polyps of African blue zoas and put them in a dimly lit area of the the 4,000 gallon tank.  After 26 days they still haven't opened.  Salinity has been steady at 1.023, nitrates are 2.5, copper is zero.  Temp steady around 81F.  Water flow around them is very good, probably a foot per second.  The water is on the clean side but there is also a fair amount of film from dead diatoms on much of the rockwork and bottom.  The tank has only been cycled for a few months.

 

The film of dead diatoms could be the cause, yet it hasn't caused nitrates to rise.  A water change is out of the question, too much volume.  I will probably put in a carbon filter just as a precaution.  I think the odds of chemical warfare are low, there are only 10 gorgos and 5 sponges in 4,000 gallons and the tank has 1,000 pounds of rock.  The rock had been stored outside and there were some dead walnut leaves in it, so there's a small possibility that there was some contamination.  Although walnut has toxic compounds (juglans) I think that possibility is very small, the rock was well washed and two months of microalgae probably absorbed most toxins.  Because the tank is in sunlight it caused the first couple of months to be "pea soup" green from microalgae, but the gorgos and sponges cleared that up so much that one of the sponges recently turned grey, perhaps from lack of food, and I threw it away.  Now a second sponge is showing light grey around its surface.  A month ago I put an 80% shade cloth over the greenhouse to control temperature, so it is dimly lit.

 

The system I bought the zoas from had big temperature and nitrate spikes from a failed chiller, so the zoas came in quite stressed, but 3 weeks should have been ample recovery time.  And I think African zoas tend to be hardier than others.  The gorgos show no signs of stress.

 

Any help would be appreciated.

 

Dave

Edited by dave w
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26 days is long time. If they were mine I would not handle them because In my experience they are one move away from melting. I have had luck

turning all pumps completely off. Mix a mild Lugol's iodine/saltwater mix in a syringe and gently cover them in that solution for a minute, then start to turn the pumps back on. 

 

There is certainly a chance there is something there bothering them keeping them closed, zoa pest are hard to spot. 

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The zoas are on half a dozen rocks set up 6-12" from each other and they got a Bayer dip upon introduction.  They could still be irritated by pests but I haven't seen any.  I think other causes are probably more likely.

 

But I could be wrong.  Keep up the ideas and I'll keep on the lookout to see if they have pests.

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Your system has lots of variations from what people normally see in a reef tank.  Most of them are small and our amateur knowledge suggests that those differences are ok.  However, maybe something like walnut leaves really are a problem.  Maybe the combination of some of these variations is an issue. 

 

I would take a small sampling of the zoas and put them in an established, successful reef tank and see how they do.  Think of them as your control sample in this gigantic experiment of yours.  If you can't or don't want to, then maybe you should eliminate some of your more significant variations like lighting.  You can find a spot that doesn't get the sun exposure and use a good MH fixture for a few weeks to rule that out.

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I had a lot of problems keeping corals in my new tank when it was less than 6 months old. I would just chalk it up as new tank syndrome or you will drive yourself nuts with all the details.

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take them out and soak them in a hydrogen peroxide solution. works wonders for me and my zoas. on a small scale usually I put 1 cup to 1 gallon in a container to soak for 15 - 20 minutes. this is for treatment, for maintenance after water changes I use 1ml per 10 gallons of system volume, this is done probably once a month.  

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maybe the 81 degrees that you're keeping them in is simply too hot. Brendans system was 77 and those zoas were thriving.

 

I've read that the African blue zoas thrive in cooler temps. I'll bet that's it.  

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Think of them as your control sample in this gigantic experiment of yours.

 

This is solid advice.

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There was an article in Coral Magazine a few years back and they said blue zoas thrive in lower light. I know you said you have them in a "dimly lit" area but how dim? You got a PAR reading where they are? I don't think a knee-jerk dip is going to help them unless you can see something visible on their surface such as a pest or disease. Use a magnifying glass. I have seen dips hurt or kill zoas. Without the benefit of seeing them myself I would not rule out the light as the culprit. Too much? Too little? Even blues need some light.

 

Look for these:

 

http://www.zoaid.com/gallery2/main.php?g2_itemId=384

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Thanks everyone, for the good advice.  I'm doing my best to cool the tank but in our current heat wave the temps have gone up to 82.  It may be a week before they drop back.

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Hey Dave, 81-82 is pretty high a temp.  I would think that this is your most likely cause.  Are they still intact or are you noticing any deterioration?  If these are still fleshy, just take some and put them in a bucket of water and see what happens if you aerate it inside the house where it's cooler.  Graying sponges sounds kind of odd in terms of starvation, sounds like they have something else going on with them.  In my experience colorful sponges don't turn grey and then die, they simply start to deteriorate and fall apart or simply don't grow, although my experience with sponges is pretty limited.

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Hey Dave, 81-82 is pretty high a temp.  I would think that this is your most likely cause.  Are they still intact or are you noticing any deterioration?  If these are still fleshy, just take some and put them in a bucket of water and see what happens if you aerate it inside the house where it's cooler.  Graying sponges sounds kind of odd in terms of starvation, sounds like they have something else going on with them.  In my experience colorful sponges don't turn grey and then die, they simply start to deteriorate and fall apart or simply don't grow, although my experience with sponges is pretty limited.

 

Interesting. I have been having temperature problems lately too (81 or 82F) and my orange zoas are closing a bit. 

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