Weird critters during the night? Harmful?

[ant81]

I was looking at my aquarium during the night with a flashlight and I noticed tons on critters on my sand and live rock. They are the size of brine shrimp some are a bit bigger and they crawl into sand and live rock. When the bright light goes on them they go hide. I was wondering what could it be and is harmful?

 

[Toddrtrex]

Either "pods" or mysis shrimp, harmless. When a tank is first set up you will have a population explosion of them. Over time the population will fall back to what your tank can support.

Do they look like those at all?

 

[SushiGirl]

google copepods, amphipods, and isopods. It's probably a mix of all of those.

 

[Sugar Magnolia]

Have a look here - http://reefkeeping.com/issues/2004-08/rs/index.htm

 

[ant81]

Yes they look like the pic in the post

 

[ant81]

Either "pods" or mysis shrimp, harmless. When a tank is first set up you will have a population explosion of them. Over time the population will fall back to what your tank can support.

Do they look like those at all?

Yes they look like that exactly

 

[SushiGirl]

Yes they look like that exactly

Those are amphipods, just so you have an exact ID.