moving strings, what is this ?

[rafaelpty20]

I notice my tank has some yellowish strings moving, and they are not small serpent sea stars, they all over my sand bed, and when i feed my fish, and food fall to the botton they wrap around it
https://s23.postimg.org/od2j3tqcn/20161225_184724.jpg (https://postimg.org/image/od2j3tqcn/)

Also you can see it in the video https://youtu.be/vM_F1VnhuJo

[heathlindner25]

I wouldn't worry about the worms and focus on the aptasia .

[AlSimmons]

Those yellow strings your seeing are probably either a Terebellid or Cirratulid worm, both of which are harmless.

http://www.lionfishlair.com/hitchhikers-guide/

[Ron Reefman]

Don't sweat the spaghetti worn, it harmless. I wish I had a few.

But as Heathlinder said, get after that aiptasia in the back of the pic!