Help with bug ID

[sa52]

Well today I happened to be walking by my tank and saw was looked like some sort of bug floating in the water. I grabbed my coral feeder and pulled it out. I could not ID what it was so decided to pull a small live rock I had and dip it and see what came off. There were a few things that came off and look similar to what I pulled out earlier. Want to know what it is to see if I should worry about my acros?

 

[Rob.D]

Amphipods, Harmless detritivores.

 

[redfishbluefish]

Picture is out of focus....but the bottom two are definitely amphipods/copepods.....good stuff. The top one is too out of focus to tell what it is.