Web spinning worm?

[RoTTen2TheCore]

Ive noticed this little worm like thing in my tank a while ago and now it has gotten bigger and seems to have a few friends, when it was small i thought it was just a part of the liverock (because they dont move) but as it got bigger it seems that it secretes a thread like slime that it uses to filter feed. ive seen them catch little pieces of shrimp and slowly pull the thread in to eat. They are white and are stuck to the liverock. anyone have any idea what they are?

 

[greenbean36191]

They're vermetid snails. They annoy lots of people and in large numbers can irritate corals, so lots of people crush their shells to kill them. If they don't bother you or your corals there is no real need to kill them.

 

[drummereef]

Vermetids.
http://www.reefkeeping.com/issues/2005-01/rs/index.php

 

[jcoat]

i am having the same problem with these little pests right now and it is not fun at all!!! they will not stop multiplying!!!!!! i kill 10's to 20's of them everyday.....and by morning...POOF there are another 100 of them! i EVEN HAVE THEM GROWING on my snails shells and crabs shells! It is becoming a big nuisance! anyone know what contributes to their reproduction??

 

[drummereef]

Overfeeding is usually what promotes reproduction.