Help! I can't identify these circular, bug looking things that are in my fish tank

i haeve weird little things in my gravel too. They look like ant eggs, but i haven't fed my fish ant egss since ages ago. One was moving around today. I hav no i dea what they are
 
Pics would help but I know that's not always an option. On the upside, not all bugs and unintended aquatic guests are dangerous.
 
PICS!!! could be amillion things without pics
 
AquariaCentral.com