Curious what are these?
 

https://fbcdn-sphotos-c-a.akamaihd.n...68466812_n.jpg
I have these on my Emerald on Fires and apart from looking like a plague they have never seemed to bother the zoa? Curious what they are. They don't affect any of my other zoas or in the tank anywhere.

looks like some sort of sponge

Looks like maybe dead colonial hydroid tubes? If so, and no "fan" comes out the end, then they are likely dead hydroids (good thing). If the "fan" does come out the end, they are similar to Aiptasia in that they sting surrounding corals and may spread rapidly. Are the tubes soft? Colonial hydroids have soft tubes.

A pic with the "fan" out (they appear clear when the hydroid is retracted or dead):
http://img52.imageshack.us/img52/1243/hydroids.jpg

I was thinking along the lines of a sponge as well but they are tube like:question:

Hey myka,

I have never seen them any other colour then white, and never have had anything extending outwards.

I would tweeze or scrape off anything on a zoa plug thats not a zoa,not a lot of realestate there!:biggrin:

I do clear the zoa with a razor blade of these things and a week later they're back! To be honest when I got this frag there was nothing and they didn't grow and non existent, It wasn't even coloured and struggling when I got it 5-6 months ago, since its regained its color and thrived these things have been growing?>

They could have been dead when you bought the frag. I have a few dead colonies about that size on some of my live rock.

Good advice. :)

I will get scraping again, haha

Also posted on RC see if anyone over there might know..

Sponges will die when exposed to air(but only the ones you want).but all sponges feed,If you have a high nutrient or older system they're just chowing down.Here's something I've done(if you have the means)pick off as much as you can, put the frag in your salt mixing container for a week(lit, heated, and circulating).The new salt water is essentially devoid of anything a sponge will feed on and should die off.Zoas will be fine.

its a sponge that grows on zoanthids i have all kinds of it in my grow out system , if left alone it will smother the zoas and kill them , besides that they are harmless and photosynthetic.

overtime it can weld liverock together(found this out the hard way lol)

Well guess I know who I got it from :wink: Kidding.

Okay well how do I rid it...Denny or do you just leave it, I think its sort of sweet looking. but one frag I can deal with if its hits them all i'll pull my hair out.

Most def could have came from me, result of feeding large amounts of phytoplankton and I meant not photosynthetic, it grows in the dark and filter feeds just trim it off and slack back on the nutrients mostly harmless :)

Now that you mention it I will add however my nitrates are quite low but I have been spot feeding all my corals with phyto and the melt off of the food i've been feed which name escapes me right now. mrhasan did a post on it recently grr... my memory is going down hill!:razz:

Ocean fresh pacifica plankton great food I use a lot of, its def the phyto sponges love it;)

Are the tubes easy to pull off? If they are easy to pull off they may indeed be tunicates (sponges). If they are stuck on there pretty good then they are probably hydroid tubes.

Hydroid,or even vermatids i was thinking at first,but those Zoas would be so stung that pic from OP would look a lot differant.:smile:

Thats IT! haha sorry pure this was in response to denny on the food

They are very easily pulled off with a razor just scraping. Tunicates I looked at and did some research from my understanding tunicates have a outer shell and on the tubes there are 2 openings, I also figured tunicates to be much larger! Do tunicates have any movement response when touched or scraped these don't move, don't close and don't FIGHT

What happened!:neutral:

A 1 hour air bath will kill a tunicate then.zoa will be fine.

Try just pulling with tweezers. Tunicates and sponges are delicate, hydroids have a surprisingly tough tube. If they are just dead hydroid tubes, there is no need to remove them unless you find them unsightly. If they were live hydroids they would be stinging the poop out of the Zoas.

Sorry how do these things spread and keep growing if they're dead lol. I scraped them all off if they come back as I know I missed some it will be time for some oxygen therapy.

Thank you for all the info.

Clavalina sp. hard to find info on these though:smile:

They are spreading? Oh. Hmm. They just don't look like sponges or tunicates to me. Oh well, good luck with the air bath.

If all I had seen was the top of that plug I would have said hydroids as well, but when you look at the bottom of the plug you can see more tendrils that are half forked wrapping around and down. That looks just like one of the kinds of sponge I've seen dozens of times in my tank, usually in the sump where there's never any light, and the tubes sticking up above the polyps are consistent with the vents of that kind of sponge.

When the zoas are closed up for the night, can you see more white stuff in between them? If so it is that sponge, and simply removing the tube vents won't be enough, you'll have to scrape the entire body of the sponge from the plug or it will just keep growing back.

Yup scattered all throughout the single polyps while closed, I'm pretty sure they're some type of sponge!