tube worms???

[Snappy]

I have some odd looking worms? that come out in the dark and are very light sensitive. They extend out of the live rock sometimes up to about 2 - 2-1/2 inches in what looks like a tube a little less than 1/8 " wide. They have a bit of a greenish-blue hue but are more transluscent and with-in seconds of light hitting them they collapse and shrink back into the rock. I had a pretty good look at one the other night (about 4 seconds) and it looked like a straw siphoning silt off the bottom, but not so stiff as it can bend itself. I have only seen 3 so far but I have no idea what they might be. Does anybody have any idea what these things are?
Thanks,
Greg

[Snappy]

I think I have found out what my nocternal mystery is.


Last night I looked in my tank with a flashlight and saw a small worm about a 1/4" long that unrolled itself like a sock. It was not segmented like a "bristleworm", is this a polychaete?
What you probably saw was a Sipunculan or peanut worm. It is not a polychaete, rather it is in a phylum of it's own. Sipunculans are harmless animals that bore holes in rock and are general surface moppers. For further information on these unique invertebrates, check out: http://www.aquarium.net/0497/0497_4.shtml, http://www.animalnetwork.com/fish2/a...wb/default.asp, or http://www.ucmp.berkeley.edu/sipuncula/sipuncula.html