Little Black animals

Hi i have a question the other day i got home and turned on my fish tank for no reason. All the fish were sleeping i think lol and i just looked at the live rock when i seen something really tiny swimming/flying in the water then there was a longer one but they went into the live rock before i could take a picture. So then a couple days later i went in the middle of the nigth and turned the light on and saw like 7 to 10 of them but they scattered and all hid in the live rock. Well my question is does anyone know what those things are and are they harmful for my tank

I have a 45g. tank with over 45LBS of live rock my Ammonia is at 0ppm, Nitrite is at 0ppm,PH is at 8.4, but my nitrate is at 40
I have 2 maroon clowns, 2small yellow tangs, 2 four striped damsels and 1 blue w/ yellow tail damsel

 

maybe they are copepods or something get a pic if you can!

 

Most likely some form of copepod or amphipod. Could even be mysis shrimp!

Either way - harmless if it is any of the above.
Pictures are the best way to get a solid ID.

 

+1 above yeah i agree with that like i said and him prob just cope or amphipods but yeah they are harmless

 

Free fish food.