worms

[langcjl]

I got a new rock from the LFS which has really good life on it. There are a bunch of little serpent star type critters and some slug like snails. The things I am trying to identify are some type of worms that stick straight out of the rock when the lights go out. They are very thin, like a hair, and white. When I turn the lights on they slowly pull back into the rock. They are between 1/4" and 2" when extended. Anyone have any ideas on what they are?

 

[steven the fish]

Are there a bunch of them?

 

[langcjl]

yes, they are all over the rock. white, very thin and delicate/lacy looking. pull in slowly when lights go on.

 

[oregonbud]

They sound like nematodes to me, there are literally hundreds of species of nematods, so a definite ID on the actual species you have (you may have more then one species as well) would be extremely difficult. I have tons of these worms too, sometimes you will even see them swimming in the water, and they are very small, almost like a piece of hair, the first time I saw one I thought it was hair until I saw it move over to a rock and go into it.
This site has some pretty good info on marine worms that are common in the aquarium - might be able to find some more info there - algone.com/worms.htm
HTH,
OB