Zanclea Hydroids

[Alexraptor]

Discovered that one of my Acro frags seems to have a wee Zanclea margaritae infestation going on.

The information I find about these hydroids is a bit muddled and unclear. Scientific sources seem to indicate that they live in symbiosis with the coral, and some aquarists say that they are harmless and only present an aesthetic issue. Others however seem to indicate that Zanclea Hydroids have harmed and killed their colonies.

Can anyone help me figure out what's what? Are my acro's in danger or is it fine? should I remove the infested frag or leave it alone?

 

[acesq]

I recently had a stag that developed a Zanclea infestation, its health definitely declined to the point I was worried I would lose the whole colony. I cut off the infested portion, dipped it in Revive a few times and kept it in my frag tank for observation. Both the fragged portion and the colony are now Zanclea free and doing well.

 

[Alexraptor]

Hmmm sounds troubling. How great is the risk that they spread to other acros in the tank?

 

[acesq]

No idea. I didn't want to take any risk so acted quickly.

 

[happyhourhero]

I have them on one coral in my tank. It came in on a frag I won online and has remained on that frag only. Has been in my system for about 7 months. Affected coral has great growth but horrible coloration. Not sure if it is from the hydroids or just the fact that it was a chopped up wild colony that doesnt like my tank...

 

[Alexraptor]

Yeah not easy to tell, but glad to hear the colony is growing well, that's a bit my main concern. We seem to know so little of the relationship between these organisms.

I think I'll let the frags be for now, in the name of science.
Color seems to be ok(its brown with green highlights not super exciting lol) and they are growing, several of them starting to encrust on the rock. I'm also seeing good polyp Extension and no signs of tissue necrosis or recession.

 

[minus9]

I had them on my a. exquisita frag. At first the frag was growing and doing fine, but then it started to decline rapidly and had to pull the frag. When I broke off the frag, there was some new growth left over on the LR, so I decided to let it go and see if it would survive. It held on and slowly started to grow, free of hydroids. Let me find some pix before and after.

 

[minus9]

This shows the hydroids in action:

This is what was left over after pulling the frag:

.......and here is the surviving coral today:

 

[Alexraptor]

Curious, very curious.
Were they just simply "there" from the start or did you ever experience that they spread or multiplied on the colony?'

 

[minus9]

They just appeared one day. My guess is they were living in the frag when I bought it. The LFS that I bought it from had the colony for a while and broke off a branch or two when cleaning one of their display tanks. They mounted the frags and moved them to another tank that sees a lot of "fresh" corals that are maricultured or wild. That's probably where it picked up the hydroids? The colony was clear of hydroids as far as I know.
Fortunately, none of my other sps were affected by the hydroids, so it was an isolated case.

 

[Alexraptor]

Mmmm the big mystery seems to be then why some colonies are harmed by the hydroids while others aren't.

 

[minus9]

Mmmm the big mystery seems to be then why some colonies are harmed by the hydroids while others aren't.

I agree. I was hoping they would just coexist with the coral (as I read they would), but for some reason, it took a turn for the worse? My parameters we're fine, no swings with alk or SG.