One day nothing, next 1000

My guess is that they are copepods. I had a similar experience with them. One day, nothing, the day next the tank was teaming with them.Everywhere, especially on the glass.

Thats about the best time to get something like a mandarin goby, as you know the poor thing wont starve.

 

No they are small white and brown shelled snails. I have them as well. The only negative thing I can attribute them to is clogging my becket injector for my skimmer. I have had 2 outbreaks of them. once their food is in short supply they will die off.

I would not concern your self with their presents.

J

 

I uses to have alot of little dot and they grew and grew. I have alot of little snails, there're smaller then a eraser on a pencil. Now that they are bigger to see I don't think they are nassarius snail.