Id sand creature

[hapki88]

Something for the reef experts...

Recently noticed a bunch of very small things crawling around on the sand base and sometimes the aquarium walls. It appears that they do not swim, are somewhat elongated, and kind of look like a centipede. I thought bristleworms but these things are REALLY small - may be 1-2mm - can't even get a picture.

[Ron99]

Copepods and amphipods. You want those in your tank so don't worry.