Is it more like a thin thread or thicker than that? Also do you have nass snails climbing on the glass? I have found that mine will leave behind some white mucas every now and then.
Thank you for the replies. I have attached a picture of the "worm-like" string. I do have snails but they don't leave evidence on the glass. I am new to this site and know it will be a valuable tool for my hobby. I have a Nano-Cube 28 Ga