What is this?

[GeorgiaMan]

Hi all,
Well it's been a while since I posted here, (If it wasn't for work, I could really enjoy my tanks more!) I have a small sick tank that I stocked with Live Rock and a couple of Camel Back Shrimp. The Live Rock I purchased on Line was exceptional with lots of growth! I have something growing however that I do not have a clue what it is! It is too small to take a picture of so here goes with the explanation. I have multiple very long, 2 to 3 inches, strands that are translucent white. They have several small nodes all the way up. They will contract when touched down next to nothing then release back out again. (Must be alive and not a plant) I do not see any type of tube on the rock, they just seem to be attached to the surface. I thought at first that a string had gotten into my tank until I realized it was “Alive”. If anyone knows what this is, please let me know.

[OrionGirl]

I'd get the camel backs out right away--they tend to be really hard on the micro fauna, with worms being their number one snack.

In therms of ID'ing the critter..Sounds like a type of worm. Are they inside a hole at all, or just on the substrate? Approximate size?

[GeorgiaMan]

I don't really see a hole that it is in, it looks to be attached to the rock. I would say that it is about 2 inches long and about as big around as thread for sewing. There are about 4 of the strands that are there and seem to be coming from the same place, but they could be side by side. I just can't seem to find anything close to what this looks like.

[OrionGirl]

Hmmm. Is there a stony lump at the base, that they retract into? Could be what I call a carbuncle--that's not it's real name, though...They are a stony cnidarian. check here: http://aquariumboard.com/forums/showthread.php?t=39

[mr_fosi]

Could they be juvenile vermetid snails?

http://www.reefs.org/library/aquarium_net/0897/0897_8.html

[mogurnda]

Maybe ctenophores.
http://www.wetwebmedia.com/Cnidarians/Hydrozoans/Hydropolyps/Ctenophore.jpg

[GeorgiaMan]

Mogurnda,
That would look like it if there was not any Side Branches. Also, it is waving Snake like. and there may be a stony base.

[GeorgiaMan]

(They are a stony cnidarian) Is this good, Bad, or neither?

[OrionGirl]

Neither--if that's what they are, they're just a part of the common hitch hikers, neither good nor bad, just part of the critters. I guess I'd say more good than bad. :)

[mrsdorothy]

Does it look anything like this?

http://www.imagestation.com/picture/sraid205/p5fee01dcd35049f96cdd2f34d52bfb1f/ef0aabe4.jpg

This grew on my rock and I have no idea what it is.

[GeorgiaMan]

Not really. There are several strands coming from a single place. Each strand can be as long as three inches but it will contract to nothing. It is white and looks like it comes out of the rock. I know that it has to be alive because of the way it extends out and then back in. It never gets any wider than a piece of thread.