Sponge-like Growth On Zoas

chipmunkofdoom2

Well-Known Member
Hello all. Having some issues with my blue zoas that I've had for a couple months.

There are two colonies on the same rock, one a tad higher up than the other. The one colony had been looking kinda angry for the past couple days or so and at first I thought nothing of it.. they had done that before and bounced back and looked fine. Well, one or two of them have now melted away completely, and after feeding today when they were all closed up, I noticed an encrusting-sponge like growth on some of the zoas. It doesn't look like nudi eggs or anything like that. It looks closest to a sponge to me.. the pictures may not reflect this though.

34shvv5.jpg


157ymg5.jpg


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The other colony, not even an inch above this one, on the same rock even, shows absolutely no signs of stress. Tank is 29 gallons, 130w PC lighting, 2 Koralia 1's for flow, no major changes in over a year. Zoas have been in the tank and happy for probably 2 or 3 months now. This is the first they've really had any issues.

Any ideas? Thanks :hallo:
 

chipmunkofdoom2

Well-Known Member
Yup, I've searched all over this forum and the net and can't find anything that looks like what I have. The pictures in that other thread look more like spirals and seem to be on one zoa. The growth in my tank is straight and tube-like for the most part and branches out in other directions. The mass appears to be larger than the last picture as well. It extends below some of the lower polyps and all seems to be connected.
 

chipmunkofdoom2

Well-Known Member
It really does look an awful lot like a sponge..

I read about a "zoanthid killing sponge" on one forum but since that's the only place I read it... I'm not sure what to think.
 

cbrownfish

Well-Known Member
There are many species of encrusting/invasive/boring sponges. I have never heard of one that targets polyps but I have seen sponges between my zoas and then watched the 2 fight for dominance. Without a little higher resolution macro it is tough to draw a distinction between an egg mass or sponge just viewing it here. It does appear to be more sponge-like to me though.
 

tnwillia

Well-Known Member
Look like this? I've got them all over my rocks. I was told they were sponges and not a problem. But, they do go wild now and then and they have wrapped around some of my zoas & polyps. They are growing thru every open hole in most of my rocks. They seem to line the holes, once they have the outside section of the tubes break off. Good luck!

DSC01389.jpg
 

chipmunkofdoom2

Well-Known Member
Yes, it resembles them. I will attempt to take the rock out tomorrow and see if I can't get a better shot.


After the feeding, the polyps went back to their normal open self, and if it weren't for the bald patch where a few were missing, I wouldn't even know the offending "stuff" was there.
 

chipmunkofdoom2

Well-Known Member
Yup, that looks like them. Thanks for the great picture. Mine look smaller, but texture and arrangement are very similar. I can't even tell they're there now since the zoas have opened back up and are looking great again. I'll keep my eye on them and do a dip or something if the problem persists.
 

tnwillia

Well-Known Member
Terry... I've not tried to get rid of them other than the random piece that works up onto a coral. I can't remember who told me they were good but they said that sponges growing thru the rock was a sign of a stable healthy tank. So, I figured I was doing something right and not messed with them. But, I could be wrong, won't be the first time.

Chip... good luck what ever you do with them!
 
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