Surprise siphon in live rock

[grizfamvac]

Hey gang:

I am re-entering the marine aquarium world after about a 17 year absence (read KIDS), and have done a lot of the required reading, and now have a new 80 gal set up that will eventually become a reef system (just live rock and cleanup crew right now). Her is my question. I have some tonga live rock and was surprised to find last night a 2-3" siphon from one of my pieces reaching down into my sand. When I shined a flashlight on it, it recoiled and didn't come down again until the lights were out for quite a while. I can't see what it is coming out of because the rock is suspended by 2 other rocks to make a cave, and the sipohn is coming out of the lower, back part of the rock. Any ideas what this could be? I assume it must be some sort of boring clam. Anyone else see this before? Any clues are appreciated.

[Staghorn]

Hello and WELCOME :) Was the siphon the same diameter from top to bottom ??? If so it also could be a worm i've seen in the live rock that only comes out in the dark, first they eat whatever they consume ??? around the hole that they come out of then as they exhaust this supply they countinue to reach out further and futher consuming. I have never seen them all of the way out of their hole but i've seen a whole lot of them stretched out and then withdrawn when flash lighted ??? Don't know what they feed on and i don't know how big they get ....... :confused: Anyone else ???? Also does this tube look like it's banded w/ light and dark rings ??? Check out Dr. Ron Schimick's lastest article on Bivalves : http://reefkeeping.com/ this on-line magazine has his article. Let us know what's up !!!!!!!!!!!! Staghorn :cool:

[treylane]

Could be any number of critters. My favorite "tube extending" critter is the peanut worm though... they extend what looks like an elephant's trunk with a couple little fingers at the tip, and can stretch it quite far. They seem to be relatively common.

[grizfamvac]

I've done a little more checking and I am pretty sure it is a peanut worm. The siphon is proboscis-like, 2-3" long, and tan/yellow. It is definitely foraging, and has stirred up the substrate below it. Hard to get a good look at it since it shies away from light. A nice feature for the tank, even if it is largely invisible. Now if I could just get a crackerjack shrimp. . . . .. .

[treylane]

You mean a pistol shrimp?

[grizfamvac]

No--I was just making a bad joke--"buy me some peanuts and crackerjacks. . . " :o

[zenreefer]

i have a strange worm or ? which lives in a large pocket in my live rock. it looks kinda like a snail ( without the shell) or sea slug. it is very sensitive to light and retracts slowly away from the opening.

i have no clue what this ting is. it is not a segmented worm though. anyone want to guess what it is?