ID Question

[marine qa]

When I came home today I found a 1/2inc red worm? of sorts swimming quickly around my return pump in the refgium sump. When I cought it looked a little like a centipede. It is a good swimmer. It must have bee born from existing LR or LS bc I haven't added anything to the sump in awile.
Any Ideas?

 

[nm reef]

Nothing to fear....sounds like a brisstle worm to me.......not a danger unless they get really big...pretty common on lr........got several in my system and they've not been a concern......