I might be missing something, but I'm just seeing a ton of copepods of different sizes.
I could be missing it though... these videos and pics people post make me feel like I'm looking at a Where's Waldo puzzle half the time when viewing on my phone screen, lol.
The small "fleas" are copepods which is awesome and the bigger one crawling down with all the legs is a munnid isopod which is another good guy. I have loads of them but wish I could see that many copepods.