Worm - friend or foe?

[AngiGiles]

Found a couple worms in the bottom of frag cups - haven't dipped yet, but will be. Who's this?
And this guy? Small, hard to get a pic.. wiggles A LOT

 

[Cali Reef Life]

Looks like a bristle worm they kinda are both. Good for tank bad for hands. There are hundreds of species some are good for tank eat detritus but others are bad. But make you itch badly if touched. You gotta look up if want it or not either way you will have some in your tank eventually even with dips.