what is this?

[Billy1205]

Anyone know what is this things growing on my live rock?
How to remove it?

 

[stingeragent]

Vermetid snail. Generally fine to keep them.

 

[CafeReef]

Vermetid. Good guy no need to remove

 

[stingeragent]

This is a good guide for future reference. http://www.lionfishlair.com/hitchhiker.shtml

Also a few other good ones out there. Just google, "reef hitch hiker guide"

 

[Reefermatt3]

Those are vermetid worms. Although they are not harmful they can agitate corals when they release a web in the water column to get food. The easiest way I found to remove them is to use a pair of tweezers to pluck them off.

 

[Billy1205]

Luckily it is not harmful, this thg worry me out.
Will this vermetid worm grow longer if I just leave it and does it spread around the tank?

 

[cloak]

They pretty much just stay like that, but the more food that's available to them the higher the population will rise. This generally is not good.

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