I've had one of these start to eat Astraea snails. If they can get them to remove their foot from a rock, they will cover the operculum with mucus and suffocate the snail then come back and eat it after it starts decaying. Other than a hand full of snail deaths, he was never a problem.
Neat trick! Periwinkles (another snail from same general habitat) will do a trick like that when they're out of water during low tide to keep from drying out. Wonder if your snail might have made the slime as a "last gasp"?
Also good to point out that they'd never get a healthy snail that way. Keeping them healthy isn't so easy as Astraea are cold water animals and would really need a large supply of algae to stay healthy long term. In most systems, that's two "dings" against them. There are
more appropriate snails if you have trouble with Astraea. Personally I would stay with snails that don't get as big like Ceriths or Nerites. These will also reproduce in-tank to keep up with algae issues and reproduction is fairly commonly seen. Personally I've seen Ceriths reproduce more often than anything else, but I've never had more than a single Stomatella. I've heard they will reproduce like crazy. My limpets reproduce like crazy, but I have no idea how...never seen an egg.
Interestingly (to me anyway), my bristleworms follow my snails (Cerith and small limpets) around the glass and rocks all the time, eating their poop "in real time". They're so close to each other that it looks like the snails have bristleworm tails. LOL
I know there are a few things that eat them although I can't remember what they are. I just read it a few weeks ago also (my memory is already failing me at 26 lol) just do a few minutes of reading and you'll find out what does naturally predate on the though.
Nothing reef safe is going to eat them preferentially.
Really, as others have said, there's no good reason to "try" to get rid of them. Their population will naturally follow the available food supply. So, if you have "a bristleworm problem" what you really have is an overfeeding/maintenance/overstocking/whatever problem. Figure that out and the bristleworm problem is gone.
FWIW, the critters in question are Eurythoe complanata (Caribbean Fireworms). They are generally detritus feeders, but will indeed prey on desirable micro fauna. They also have a more potent sting than Eurythoe sp. (common bristleworms).
The easy way to distinguish fireworms from bristleworms is that their protective setae (bristles) are arranged in definite clusters/tufts, whereas those of the common bristleworm appear more continuous.
Good info!
I would suggest that Hermodice sp. are the only bristleworms really worth worrying about because they eat coral. Even these should be exceedingly rare, and it'll be no mystery if you have them (
read this, paragraph 7 especially) due to the way they go about eating coral - worms have no way to bite! Also why most only eat dead/decaying matter. (Read the link!) So even these aren't worth worrying about to me...just be aware of them and remove them if you see them feeding. (Neither me, nor anyone I know in the hobby has ever seen one of these. I worked for years at a salt-only LFS that has been around ~15 years and the owner has never seen one either. FWIW.)
-Matt
P.S. To Ru11er: I wouldn't obsess over it because it's not too likely to happen, but given the chance (e.g. finding him completely out and in the middle of your sand bed) I think I would opt for removal of your big worm. The reason I wouldn't obsess is that chances are is all he'll ever do is help keep the tank balanced when feeding levels are high, etc. The only real reason to justify removal at all is that if you had to starve the tank for some reason - long enough that he would actually be starving to death - he might be big enough to worry about for any weakened or very small tank mates. Pretty unlikely scenario.
