Sponges? Snails? New polyps? What the heck is that?

[ShrimpBandit]

These have been some of the happiest, healthiest zoas in my tank until the last few days. Normally, they're a lot like the ones you can see in the background. With the polyps all closed up, I can see the clear, flexible tube things at their base. Are those the issue? I also have a suspected vandal amongst my hermit crabs...

 

[Beau_B]

sponge, harmless

 

[ShrimpBandit]

sponge, harmless

Thanks. Any idea what else could be up with these zoas, then? Nothing else in the tank is having an issue, not even the same variety of zoa placed three inches away.

 

[Beau_B]

I don’t really. I have the same problem in my tank periodically where a patch will close up while another flourish.

Vermatids could do it reportedly. Certainly a hermit.

They look stretched, even the patch behind in the photo. Could it be just a lighting issue?

An odd flow current in that spot?

 

[damsels are not mean]

Actually sometimes sponges do grow in zoanthid mats and irritate them. You might want to consider a peroxide dip or something to try and clear it. I don't know how well that works but I know zoanthids are one of few corals that can tolerate peroxide dips so hopefully the sponge is less resistant to it.

 

[ShrimpBandit]

I don’t really. I have the same problem in my tank periodically where a patch will close up while another flourish.

Vermatids could do it reportedly. Certainly a hermit.

They look stretched, even the patch behind in the photo. Could it be just a lighting issue?

An odd flow current in that spot?

Yeah, my lights are pretty basic - that's why whenever I see polyps stretching, I try to move them as high up in the tank as I can. One day, I'll upgrade, but not today.

This particular patch has been my top performer in terms of growth and this behavior has only happened within the last few days.

I haven't changed the flow or anything else, though I *did* just break off one vermetid shell nearby. Not sure if they're even in my tank yet, or if it was a dead one that came with the rock (all of which was dry for months, then soaked in bleach for a week, then set outside in sun for a few weeks, and then dry for a few more months, and so on).

The hermit was there for most of a day or two and then I noticed the first polyp acting strange. Maybe a coincidence, but who knows?

 

[ShrimpBandit]

Actually sometimes sponges do grow in zoanthid mats and irritate them. You might want to consider a peroxide dip or something to try and clear it. I don't know how well that works but I know zoanthids are one of few corals that can tolerate peroxide dips so hopefully the sponge is less resistant to it.

Yeah, I took the turkey baster to it and was surprised to see the volume of sponge material that had built up on the mat. I collected it all and removed it from the tank.

Unfortunately, this patch of zoas has spread across a part of my rock scape that I cannot remove, so no dips unless it get *really* serious! We'll see what happens!

 

[damsels are not mean]

I am not sure what regulates these sponges because they seem to just take over a specific colony without human intervention. But The cases I see rarely spread. I am not sure why they behave this way. It seems to not be a huge deal to the colony usually.

 

[ShrimpBandit]

Here's a thought: could these zoas be reacting to a newly placed leather coral? It's maybe 5-6ish inches away, but I hear they can be aggressive.