The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
They look like... well... baby snails! (Sorry... but not sure how else to describe them! Really really small miniature versions of whatever snails you think reproduced. Yes... they have a shell. And they're normally pretty light colored.)
I think I have the same thing going on in my tank. There are hundreds of tiny white dots all over my glass and on some of my rocks. They are solid white and have what looks like the starts of a swirl on the shell. I'll work on getting a picture.
I think they are marine worms, Like little featherdusters, but with little threads that come out and fish for food. They are a good thing and not to worry...