Copapod?

[OneMerissa]

Are these critters on my urchins hat pods??!! I hope! The other stuff floating around is some mysis I just fed.

 

[WheatToast]

Are these critters on my urchins hat pods??!! I hope! The other stuff floating around is some mysis I just fed.

It's hard to tell from the video, but the curved backs are characteristic of amphipods. These "pods" grow larger than the more common copepods and are beneficial scavengers/live food for your fish.