Help! Is this a friend or foe?

[Vestri]

We found a bunch of these little buggers swimming around when we cleaned our tank---but I have no idea what they are? Any ideas?
Thanks for the help!
Vestri

unknown animal 2.jpg (145.65 KiB) Viewed 6949 times

unknown animal 1.jpg (241.42 KiB) Viewed 6949 times

[Mustafa]

Friend or foe in what context? They are just harmless amphipods that live in decaying matter.