translucent flea like bug

[Patticakes]

I set up a 45 gallon saltwater tank about 3 weeks ago. The only living thing in it is live rock. If you look closely at the rock, you can see very small, almost invisible, little bugs. Any idea what they are? I'm new to this.

 

[cbicop]

they are copapods... they are a good thing and natural to have in a healthy tank.

 

[Sk8r]

some fish live on them almost exclusively: they multiply wherever rock rests on the sand. My yellow watchman and firefish won't touch ordinary food, so long as the copepod blooms run high.