What are these?

[haninja]

<span style="font-family: Arial;">I started noticing this about a month ago - white strings coming off a rock full of green button polyps. Now they are starting to attach to a nearby rock.</span>

 

[kappaknight]

Could be tiny fan worms... or a kind of algae. Are they definitely white or partially green?

 

[dorian965]

i would guess tube or fan worm also but ive never seen them grow that straight. they ussually curve around and are normally in darker areas. i have white tube sponges that grow like that but they are a little bigger.
not sure but they dont look like hydroids so thats a good thing.

 

[haninja]

<span style="font-family: Arial;">It doesn&#8217;t &#8220;do&#8221; anything. Doesn&#8217;t react to touch. It&#8217;s flexi but kinda have a rigid core and spongy outside. </span>

 

[wolfie]

Sorry Haninja. I do not know what they are and they are not in my tank. Must be on that rock only, but then that was a base rock when I first got it.

You see them elsewhere in your tank?

 

[haninja]

Wayne, they are only on that rock. Not your fault

 

[tsciarini]

sponge possibly? dont usually see them in direct light but sponges are weird... cant really be sure from the pics tho; your camera wanted to focus on the palys instead...

 

[jeep9783]

i had some like that and i was informed that it was sponges and that with my lighting it would kill them, i now have no lighting but the sps is doing good

 

[FutureInterest]

I have no idea what they are. If I had to guess... I think sponges would be as good as guess as any, but who knows... perhaps they're some freaky colonial protozoan with a deadly thirst for eating polyps and human skin. As you can see: I'm in the "kill first, ask questions later" school of thought when it comes to questionable looking reef inhabitants with a penchant for spreading.

 

[kwl1763]

They look a lot to me like a calcareous algea Neomeris sp. Yours look totally white though which is odd.

Do they look like this?

 

[haninja]

<span style="font-family: Arial;">No kwl1763, they don&#8217;t look anything like that, they are completely white.</span>