Tiny little creatures appearing in new tank

[AVVITT]

Hi guys. My tank is approx 12 weeks in from first filling. I've had fish and cuc for the last 4 weeks and all has gone swimmingly so far. Yesterday I came home from work and the tank was a bit cloudy, thought nothing of it as it may have been the sand being disturbed, however, today I noticed some really tiny white dots on the glass. I watched very closely for a few minutes and noticed they are moving.
They can't be any bigger than the very top of a hair, literally only just visible! Can anyone tell me what they might be and wether to worry or not!?

 

[Sarcazian]

It sounds like pods - all good!

 

[Ta2oodfreak]

Sounds like you have a healthy tank and pod population.

 

[rkpetersen]

Specifically, copepods. They are a sign of increasing diversity, as well as a food source for some fish and probably inverts as well. After the initial population explosion, they may decrease in numbers and not be so obvious, but they'll still be around.