What are this tiny bugs like critters?

[Mothi]

 

#1 looks to me like a tiny white ant. The back end has what looks like is transparent part. The critter is white...moving in short bursts along the glass. Size seems to vary from maybe 1/8" to smaller. Body is noticably two small circles.

 

#2 looks more like a tiny white aphid or slugs. Movement very slow in comparision to #1. Also located on glass.

 

I don't know if either of these live in the water column or live rocks since that would be hard to see. I tried to take a picture, but do you know how hard it is to get the camera focused on such a tiny object?

[birdman204]

copepods.

[Kool-cat]

I had a lot of those little guys, but many dissapeared, dont know why. I think the amphipods are eating them, cause i got a lot of aphipods then copepods

[birdman204]

They are competing for the same breeding / feeding grounds. Usually the amphipods win. Another issue is available food sources. They will create population booms and drops until the tank stabilizes and nutrient addition/regulation becomes the aquarists job.