Help Please

[pat3612]

In the last few days I noticed some of my ghost shrimp turning white like chalk now 4 have died do they do this when they get old also my corys seem to be breathing really fast all my stats are normal, also lost 2 shrimp in another tank also chalky white color all fish in this tank seem to be fine. Rest of shrimp seem to be fine normal see though color. Thanks Pat