Opinion please

[tangnut]

I have a 90 gallon, FOWLR. Recently I've noticed some white spots on the tank glass. They look like tiny snails, which vary in size. As far as I can tell, all of the fish are healthy. What are the white spots and should I be worried about them?

 

[Gwynhidwy]

Do they have a soft foot like a snail, or are they hard, white, spirals that look more like the shell of a snail?

My guess is that they are spirorbid polychaetes, harmless, common, filter feeders. Could also be snail eggs of some sort.

Spirorbid polychaetes:
http://www.melevsreef.com/id/spirorbid_worms.html

 

[tangnut]

From what I can tell they look like little snails (some of them are very tiny), with the feet on the glass and 2 little antenas. Could they be baby snails? I thought it was very difficult to reproduce?

 

[Ruskin]

It's not hard for certain types of snails to reproduce in your tank at all. There are just too many predators for them to all successfully grow up.

They do sound like small snails, I had them on the glass a lot at times as well. I dont think I would be to worried about it, but can you snap a picture to be safe?