HCA: Hermit Crab Association

I've been away at school and now that I've returned I noticed tiny white bugs crawling all over food scraps in the sand, and the second story caddy in my tank.

From what I was looking at are they food mites or springtails?? I just want to make sure my crabs aren't in any danger.

They actually got on my arms and are crawling on my computer too.

Here's a video of them on the bottom of the caddy.

https://vimeo.com/335043923

edit: There seem to be brown ones that started crawling all over my arm too.

I can't make out the video perfectly, but by their shape and the way they move, they look like some sort of mite, but not food mites. My guess would be naturally occurring predatory mites. They will move in if they have a food source, like food mites!