I’ve made a few of these over the past couple years, my first and oldest one being from March or April 2021. I’ve found copepods, ostracods, water mites, a hydra, tubifex worms, amphipods, and more! I currently have two of these right next to me on my windowsill. They’re a lot of fun and an easy way to spot biodiversity whenever you feel like it.
I do have at least one iNat observation of critters in my ecospheres: https://www.inaturalist.org/observations/133655906
I also documented a copepod releasing its young from two pouches on its side in the ecosphere (pretty low quality):
https://www.youtube.com/watch?v=8p1Kb_YFlfg
If you’re interested in how I made them or what else I’ve seen, just ask. It’s a lengthy explanation and I don’t feel prompted (I’m too lazy) to write it at the moment.