what are these things?


New member
ok, no picture, I'll get one asap.

I am putting together a fish order and want to buy something to eat something growing all over my live rock.

summary of problem critter:
hundreds of short, narrow, holllow, hard tubes growing on live rock, hermit crab shells, all shells, and frag plugs. The base of these guys are about 1/8" round and are resistant to picking off with my fingernail, but they do eventually break off.

what i want eliminated are 1/8" to 1/4" long hard straight tubes growing all over my live rock. picture the tube of a VERY small feather duster. Syringe-needle-width tubes, and they sometimes stab me when I pick up and rearrange live rock. ouch AKA @#(*&. Once one pierced the end of my finger and then broke off, and the blood was coming out of the other end of this thing into the water column. I'll admit that was cool, but these things are not.

I've never seen any feather duster-type animal extending polyps out of these things, but they're hollow. I haven't specifically looked at night.

They're brown or dark grey in color, they grow about a half inch apart or less, and they hardly break off with a nylon scrubbing brush. I can brush them with my hand and break them, but the base stays intact on the LR and I assume it all grows back.

I have a tank with softies and zoas/palys, and I want something reef-safe that would eat these dastardly spikes. Any ideas?

again, sorry for no pic; i want to order fish within next couple of days, didn't think until now to ask about elminiating these tubes with a new fish.



New member
I have the same things. They are tube worms. I have never seen the worm's "feathers" in my display tank, but I have them all over my live rock in my sump and they all have feathers. I think that they are a tasty morsel for the fish or just fun to play with. When they reach a certain size the fish start going for them. They probably don't get eaten outright but starve to death because they can't stay open long enough to feed. What is left behind is their calcified tube.


Premium Member
I have hundreds of these all over my tank. In my case they are feather duster skeletons. My copperband butterfly made pretty quick work of the animals, but the skeletons remain. I do not know of anything that would eat the skeletons. I have not thought about trying to remove them, but it seems that if you were wearing gloves you could just knock them off pretty easily.


New member
Look up vermetid snails, that's what they sound like to me too. I've heard of clogging their tubes with superglue, but if you have a large infestation that could be a lot of work. They use a mucus net to feed, and grab suspended particles out of the water. And yes, they are very sharp.


New member
ok, it looks like you guys nailed it: Vermetid snails.

the description has them at 1-3 cm,which these are not, only about 0.5 cm. But the description further says there are 100's of species of these guys, and they sometimes produce a web of silk-like threads to catch food, and I have noticed webbing appearing in the tank when i stir up the sandbed. So I think you guys have identified them.

fortunately, one of the accounts I looked up has a couple natural solutions, including this one:

"To my surprise, six months later I noted that a vast majority of the tubes were chewed down to their base. After spending a few weeks closely examining the happenings in the tank, I found that a long zebra leg hermit crab was feeding on them."

apparantly there are reports of copperband butterflyfish and some wrasses, I'm guessing such as a 6-line, taking care of them.

thanks -

Anyone else have an experience with these pests?



New member
with a little more research, Spionid worms may be the culprit, as well.

These pests I'm describing all stick straight out, away from the rock they're attached to. Sounds like Vermetid snails curl, which these don't do, and are bigger than the 5 mm length that are typical of my pests.

anyone know about spionid worms?


New member
Spionid worms are no big deal, they are mini filter feeders; not a problem at all and in fact quite normal.


Premium Member
There are a lot of different types of vermetids. The larger species are rarely found on LR while the small ones with straight tube ends that stick up are common. Vermetids are snails so they have hard shells and feed by creating mucus webs or strings to catch floating particles. Spionids create soft tubes out of mucus and silt; they have 2 feeding tentacles to capture food.