Yes, I think you are right. These marimos do look sick to me. I'm not really an expert on marimos, but perhaps you could try a fridge spa or putting a little bit of salt in their water. Also, do not give them direct sunlight, ever.

You are welcome! I haven't actually used the fridge spa yet, but a lot of people use it as a way of curing sick marimos. I think that one or two days would be best- marimos are capable of going without sun for longer periods of time, but you don't want to freeze them to death. I think the water level you had in the pictures should be good. Any water level should be fine, you just need a good amount of water in there, enough to make sure it won't freeze too quickly. Happy to help! Good luck with your marimos, hope they get better soon!