Moving threads searching for food? ID?

[betareef]

Notice these mostly when the lights first turn on in the morning. You can see the GSP have not even opened up yet.

These threads are grouped and appear to be coming from something in the GSP. The ends of the threads move about and appear to be feeding.

 

[ISpeakForTheSeas]

My first thought would be some sort of Spaghetti Worm (Terebellidae) - harmless/beneficial if so.

 

[Coldramen777]

I think they're spaghetti worms. They're disgusting and I hate them, but they're harmless.

 

[betareef]

Yep, some of the pictures I found look very similar. Thanks !!