[dougc]

Sorry for the less than stellar picture quality, but if you look carefully at the lower right corner of the pocillopora, there is some sort of critter that lives in a shell/tube. It has antennae like a snail and its shell twists around and disappears into the base of the coral. It appears to eat by secreting spiderweb-like threads that capture bits of food drifting by. You can see some of these threads streaming off to the right. If I could get a better picture, you would see that there are bits of detritus and goodness knows what stuck to these threads. I have no idea what it is, but it has been in the tank for a long time. I never noticed the web it emits as starkly before, but I think that it may be more noticable because I moved my Streams recently and the currents in the tank have changed.

[Ninong]

My eyesight isn't good enough to find whatever it is you're talking about in the photo but you seem to be describing a vermetid snail.

[dougc]

I think you nailed it. The opening in the shell is about 3/8". Looks much like figure 2 in the article. Thanks.

[FireEater]

Kill it and others that look like the one below. Though the webs are not toxic they can be quite irritating to corals, especially SPS.

I just lost a giant Orange Digitata colony to them a few days ago. They built their homes all inside the colony and the webs irritated the colony to where it was dieing off.

I had to break the entire colony apart to kill the worms and lost 90% of it. I periodically go through my system killing them.

You need some cutters as they attack strongly to whatever they want to. The Digi actually had them attached to it. Be careful you do not cause your rock work to fall over when you break them loose. I then cut the shell into pieces so my shrimp and fish can have a meal.

[Minh Nguyen]

It never bother any of my coral or clams. Just leave it be.
FWIT, you can easily kill it by injecting some Kalk into it with a syringe.

[dougc]

I'm not going to kill it. It has been there for a long time and doesn't seem to bother nearby corals. I have tons of the little ones and the corals grow right up around the tubes.

Now, valonia, on the other hand, I could live without.