What are these white bugs on glass and rocks/all over tank?

[yodav]

I've had a bunch of little white bugs all over the tank. Every day they repopulate the glass. and seem to concentrate on patches of algae that form on the glass every day it starts regrowing; But they are still everywhere else.

Don't seem to be harmful and I noticed that the amphipods are maybe eating them? (seen inside their body in the pic).

What are these? Is this a good sign? I have no fish yet still so maybe this will be a source of live food whenever that happens.

[Tired]

If you're seeing tiny little white dots that move around in jerky patterns, like their motors aren't working very well, you're probably seeing copepods. They're considered one of the best live foods you can have in your tank; just about all fish under a certain size will eat them, and some fish eat nothing else. They eat algae and detritus. Useful little guys. 

 

(For the species common in the hobby, at least. Some species are harmful to fish, but you won't encounter those.)

 

Edit: yes, they're a good sign. For a healthy tank, you want a nice big population of all sorts of beneficial microfauna. You'll probably see their numbers seem to drop a lot once you add fish, but that's just them going into hiding at the arrival of a predator, not them actually vanishing.