I'm raising some D. magna and one of the cultures seems to be faltering. A lot of them have started to sink and turn a very bright white (not just translucent). Here is a quick picture I took under a dissecting scope of one of them.

They're in potable spring water (Crystal Springs which they seem to do very well in, at least better than Carolina's) and I feed them a mix of 50mg DIH2O/1g baker's yeast at around 2mL about every other day in a ~3-4L container. I started the culture on 2/1/21. We're trying to see how small/easy of a budget we can grow them in.

I have 5 cultures going right now and this is the only one showing issues. Is this some sort of disease and if so should I quickly quarantine/kill these in case it can spread to the other containers?

edit: I added a compound microscope picture as well. She looks... gunky. It looks like she's got a bunch of fuzz floating around inside.

edit 2: Now the water is certainly contaminated with either some sort of fungus or Vorticella that are attaching to her carapace. Other daphnia have had their eggs turn completely white as well

edit 3: After talking to a friend who has also raised daphnia, I realize now the source of my anguish is from parasitic copepods that lay eggs that then hatch and crawl inside other crustaceans and eat them from the inside out

I'm going to keep this question up and answered in case anyone else ever comes across this issue