ID question

[john1214]

I’ve had these things arrived in my tank but can not identify what they are. Anyone have any ideas? They swim like eels. I have video but cannot post a video

 

[john1214]

Also they free swim only at night

 

[KJ]

Epitoke.

 

[ThunderGoose]

Epitoke.

Wow. You could ID from that image? You, sir, are a master at IDing hitchhikers.

 

[KJ]

Wow. You could ID from that image? You, sir, are a master at IDing hitchhikers.

Not necessarily from the picture but from the OP description.

 

[john1214]

Are they bad? And thank you!

 

[Oldsalt01]

Having just read up on "epitoke", I now understand they are the reproductive end of any number of polychaete worms. The fact that J1214 sez "they" swim at night indicates there are more than one, and thus may be breeding. I wonder if this should be of concern. I'm not saying they are necessarily bad, but not all polychaetes are reef safe. Just sayin...