Need help ID’ing these little crawlers

[JamieLyn17]

Hello - I need help ID’ing these little guys running around my now empty tank. I used to have 2 fish in this tank but the died a few weeks ago and I’m trying to make sure these things didn’t contribute to it. I’m hoping they are just some giant copepods or something that have had free run of the tank but just not sure.
Thank you in advance!

 

[Brit’s Fish]

Amphipods… good guys!

 

[JamieLyn17]

 

[JamieLyn17]

Amphipods… good guys!

Thank you!