a worm?

[natan]

It looks like a worm (a feather duster) to me. They are tiny (2 mm across the circular mouth) and they populate one of my live rocks. Here is a pic (excuse the quality - they are really tiny):

[Bifferwine]

Hmm hard to tell. Does it have a hard tube? If so, then it's a feather duster. You'll find them hiding all over your live rock as time goes on.

[natan]

Basically it's white strings grouped in a circle sticking out of the rock.

[fatman]

Sound like a possible description for glass anemones. Are they like tentacles that are more clear than white and arranged in a circle? Do they completely contract back into hole in the rock? Typically feather dusters have rows of circles of feather like tentacles where as glass anemones have just one row of tentacles in a circle.

[Bifferwine]

Yeah, it could be aiptasia or majano anemones. I'd google those and see if any of the pictures look familiar.

[natan]

Couldn't Google anything quite similar. They don't seem to grow in size. Here is another pic of 3 specimens.

[mrviper]

It kind of looks like aptasia. A pest anemone. You will want to get rid of it as it could cause a lot of damage to your other corals.

[yote]

Looks more like small dusters to me.

[MamaJones]

I just saw something very small like this growing out of a dead snail's shell. If I don't have any coral should I worry about it. Could it be a feather duster?

Originally Posted by mrviper

It kind of looks like aptasia. A pest anemone. You will want to get rid of it as it could cause a lot of damage to your other corals.

[Bifferwine]

Google aiptasia and feather dusters. They look very different.

If it is aiptasia, you should get rid of it whether you have corals or not. They spread very quickly and will take over your tank if you let them.