Are these Amphipods?

[jbrasch]

Are these amphipods? Are these considered a pest due to population size?

 

[penfold2]

Those are isopods. They're beneficial detritivores, and good food for some fish. My tanks are loaded with them as well.

 

[fishface NJ]

Looks like amphipods to me.

 

[penfold2]

Looks like amphipods to me.

It's a little difficult to tell because of the focus, but amphipods have a pronounced curved profile, whereas these appear to have straight bodies. Also, it's extremely common to see isopods "fight" with each other as they do in this video.

 

[EnterName]

I think I see Amphipods and Isopods, but the video compression kills every detail. You might be able to compare for yourself:

Amphipods

Isopods (quite small)
​

See section 8 in the "common hitchhiker guide": https://www.reef2reef.com/threads/guide-to-common-hitchhikers-in-reef-tanks.909223/

This is also where I got the images from.