Tiny White 6's on Glass
 

I decided to quit cleaning my walls of my tank to see what grows. I have all these little white swirly things that look like 6's. They are stationary or at least I never see them move. Looks to be a calcareous type of creature.

Any ideas?

I've had those before. They never really grew into anything. My assassin snails eventually ate them all. I'm curious to know what they are too.

Your assassin snails were in saltwater?

i can guess and say small feather duster tubes.

Thanks everyone... I think they are feather dusters. I have them on my rocks but I guess I have only seen them larger...one of the small ones looks like it is starting to have a fan out. So are these good, bad, or who cares?

They are good to have. But I wipe down the front and sides of my tank, not the back. Anything growing in those areas gets the wipe down.

Okay as long as they aren't something I should control like snails. Thanks.