What’s living in my chaeto?

[sotsreef]

Long white stringy creature living in chaeto. It retracts when I touch the water or it senses vibrations on aquaclear filter. Maybe some kind of worm??

 

[TheAquarian]

Looks like a hiydroid check out https://www.lionfishlair.com/hitchhikers-guide/ and see if you find a match. Photo is a little blurry