Wow then maybe mine are still alive. I found 2 body things in my tank. I just assumed that they were two dead shrimp. The tank is heavily planted and there are lots of places to hide so I don't see the shrimp much so maybe there's still hope!
I freaked out too, i have 2 ghost shrimp, and they are always losing their old skins...... it is normal, they are just getting bigger. They sure are hard to find though, aren't they? LOL!!!
You can tell they are about to molt when they get a bit milky colored. The whiter they get, the closer they are to molting. My shrimp usually eat their skin, so I dont oftne see them
When I was cleaning one of my tanks, or doing somethign like that, I found a shed skin from one of my shrimp. I thought I had squished one of my shrimp in the cleaning process! After doing a little reading, I discovered that they molt. Phew! I still have my two ghost shrimp and they're doing fine. Scary the first time you see one though, isn't it?
If it is a dead shrimp carcass it will often have turned pink (like cooked prawns/shrimp) by the time you have found it. If it is just the molt it will stay white/clear. Or so I have found in the past.