Help ident little critters

[oscarlvr]

this is my 6 day with my set up, ive seen these on the live rock first thing in the morning, but this morning theres 100's if not 1000's all over the sand bed, there about 1/8 ", and almost look like little sand fleas, can some one tell me what they are and if there good for the tank


thanks

robert

[mogurnda]

If they really look like little fleas, they are probably amphipods. Smaller moving dots are usually copepods. They are generally scavengers, and thrive in a healthy tank. They are good.