what are these worms

[keegoaz]

its the first night in my new tank and with the 20 pounds of new lr came a crap load of worms. i grabbed my camera and got a quick vid but these things are everywhere untill the lights come on then they make their way back to the sand bed. they are vary vary thin some parts as thin as a thread while other parts of their bodies can be about a 16th of in inch in diameter possibly more. they also can swim i have never seen this before they wiggle a small portion of what ill call a tail vary fast. if anyone knows what these are let me know asap i would really like to know if this is going to be a problem or not.

here is the vid with them on the sand and glass ill post again in a bit with one of em swimming
http://img190.imageshack.us/i/mvi0540q.mp4/

 

[keegoaz]

ok here is the second vid

http://img190.imageshack.us/i/mvi0541e.mp4/

 

[keegoaz]

i also forgot to mention the length of these things they are anywhere from about 1-5inches in length

 

[rssjsb]

It's a developmental stage of a bristle worm - google epitoke.

 

[keegoaz]

so do you think i should try to trap em and get em out i would at least like to dwindle their numbers a bit right when i turn on the lights they are everywhere probly about 50 of em in my solana