Fishing at dawn, young Eunice

[sim]

I saw it last night and set the trap. It didn't look like a worm to me, and in any case, the tank has too many mouths to feed while we wait for September...

 

[Gumbies R Us]

@ISpeakForTheSeas

 

[ISpeakForTheSeas]

@ISpeakForTheSeas

Definitely a polychaete (bristleworm), but not a Eunice worm.

OP, is that first pic the head of the worm? If so, it would likely be a fireworm (assuming that's a caruncle visible in the pic - for telling if it's a caruncle, see below).

For a relatively easy way to tell if they're fireworms when you have them trapped like this - look for a caruncle (a little sensory organ on their head):

Yeah, I would guess that's a fire worm - it seems to have a caruncle, so that would be a fireworm; but I can't tell for sure from the pic. To verify if it has one, see the link below:
https://www.reef2reef.com/threads/anyone-know-what-a-fireworm-really-looks-like.799596/#post-8519556