~~~ WhAt Is ThIs?: MARINE EXPERTS~~~?

Question

They look like small salt grains. They are attached to the Media inside my tank(ex. powerhead). They are very small.
At first i thought it was live sand but then i tried manually removing it but it wouldn't come out. They are very small tough salt looking grains..

If you know what they are:
Are they harmful in anyway???

Answer 1

I think if you look at these closely, you'll see they are in a whilte coiled shell. If they're what I'm thinking, it's a tiny fan worm (like a feather duster) that will grow on every piece of equipment in the tank, on the undersides of any rock, and on the glass. There are a few photos of them in this article: http://www.advancedaquarist.com/issues/aug2002/invert.htm

They're called Pileolaria, and other than being a nuisance to clean off, they're harmless.