I just put my LR in and am waiting for the sand to settle. I noticed a couple of these guys inching along the glass. I am assuming they are harmless, but best to check. I looked over the worm ID threads and found nothing, so I am throwing it out there.

tape worm!!!
nah idk but it sure does look like one.
i suggest you throw it out

O NOES!!!! TAPE WORMS!!!!!

Any other ideas?

nobody has anything on this? I figured it was fairly common

look here

http://www.chucksaddiction.com/hitchworms.html

ribbon worm

I think you may be right. Do you usually leave them in? I have read that they can be predatory.