worm things...

Question
So I read the answer saying that what Lara had in her tank was "probably a polychaete worm, possibly a terebellid or a serpulid."  Her description matched my worm thing pretty well, though mine are floescent orange and there are a ton of the "thread" things all over the tank.. now I know what they belong to.  But I'd like to know a little more about them.  The "threads" started showing up a month or so ago, and now they're all over the tank.  But tonight an entire worm was out, on the glass wall.  It squirted a ton of white stuff and its body mass reduced significantly.  Are these things sexual reproducers and could they be bothering my soft corals?

Answer
Hi Hailey. What you are seeing in your tank are hair worms( the worms you have are actually classified as cirratulids). They are harmless scavengers that feed on particulate organic material. I am not sure of the breeding behaviors of these worms in particular however most polychaete worms use both sperm and egg reproduction as well as having the ability to reproduce by division.(which may be what you saw) Don't worry about your corals. They won't harm them and are completely reef safe. Although they may get eaten by any fish you may have from time to time.