Brown worm like things laying on the bottom of the tank??

Question
Just recently we have noticed these brown c shaped things laying on the sand on the bottom of the tank. They look like small fat worms, but they don't move. they honestly look like doo doo....lol...Do you know what these are?  Are they harmfull? Thanks,
Whitney

Answer
Hey Whitney,
Lol... Well, you could be right and it is waste... or it could be a worm. Do they move? Honestly without a picture I cant be a whole lot of help with identification. Try doing a google image search on aquatic or marine worms. That should get you going in the right direction. Or take a clear picture of the little critters for me and I'll see what I can do for you.