What kind of worm is this?

[voliv006]

This little guys is a super fast swimmer and is segmented.
I haven’t been able to find anything on it was swimming around my tank at night and dropped to the sand bed as soon as I flashed my phone light on him

 

[ISpeakForTheSeas]

Probably a bristleworm (polychaete) epitoke (the reproductive life stage of a bristleworm), but a few kinds of bristleworms can swim regularly as well.

The pic's too blurry for me to narrow it down beyond that - sorry.

 

[Reefkeepers Archive]

Probably a bristleworm (polychaete) epitoke (the reproductive life stage of a bristleworm), but a few kinds of bristleworms can swim regularly as well.

The pic's too blurry for me to narrow it down beyond that - sorry.

I have a few worms that have a similar behavior, notably the dorvilleidae worms and whatever that very spiky refeugium/Acanthophyllia worm was. (You know what I'm talking about)

Also that unidentified yellow/black worm that I showed you awhile back

 

[jabberwock]

When in doubt, leave it out.