What are your water parameters?
Those nitrates are high. Maybe time for a water change?
If they are turning white, it's usually a bacterial infection.
milky white stomach = pick out and toss. sorry to say but thats the way to save the rest of population
is that some sort of lobelia plant in last picture ?
It's muscular necrosis, which can be caused by bacterial infections or unhealthy water parameters.
Database of shrimps diseases, symptons and treatments
What temperature do you keep the tank at? Higher temps can make shrimp more prone to infections.
Dwarf Shrimp Water Parameters ? DiscoBee
Note the water parameters for the yellow neos (red cherry) and CRS. TDS is important too.
Minocycline (found in Mardel Maracyn 2) is usually regarded as the best antibacterial for shrimp. Followed by Oxytetracycline, then Tetracycline.
How long have you had the yellows? I'm surprised the yellow Neos are dropping before the CRS are given the water parameters. Unless the yellow neos happen to be new imports.
Might be a bacterial infection that needs to be treated to prevent more shrimp getting infected and dying. Use one of the meds I mentioned in post #8. They have all been noted to be invert safe (feel free to ask on a shrimp forum). Minocycline (found in Mardel Maracyn 2) would be the best of the three common tetracycline group.
Yeah that's it. Pricey med, but is better than the rest. When you think about how much money it saves from saving shrimp lives, it may not seem as bad. I don't know if there is another cheaper product that uses Minocycline as it's active ingredient. BgAlsPets should have it cheaper than Amazon (but then there is shipping cost if you dont spend enough).