Amphipods?

[Crestline]

I have these little guys all along the glass in the sandbed.

Have a few in the sump as well. They appear to make their own little cocoon type of thing when there is no sand available.

Spotted a couple that are much darker in color, almost black, but couldn't quite get an angle on them to record.

 

[Arkayology]

Yes, these are amphipods. It looks like the one with the red patch has eggs.

 

[ISpeakForTheSeas]

Agreed with the above - amphipods, and the one is berried (carrying eggs). Should be harmless/beneficial.

Also, great video!