Guys, this is a little odd but my Peppermint Shrimp keep disappearing. I can't figure it out. I added 3 PS to my tank and after a couple of weeks all of sudden there was just 1. The PS have always had their own little spot in the back of the tank where they hang out and bam... two vanished. About two months ago I added 2 more to be back at 3. Everything was good. they were good, happy and eating. Once I heard a splash while watching the tank at night and realized one of them had just spawned. There was hundreds of tiny PS everywhere ( of course none of them made it) I noticed a week ago only one was visible (the small one) It was odd to see one out on the side of the glass slightly above the rocks but still towards the bottom. That was a the last day I saw any of them. They are all vanished now. I have had 3 Sexy Shrimp and a cleaner shrimp the entire time and not lost any of them. There is no top on my tank but there is still maybe a good half an inch from the water level to the inside lip of the tank. I've looked everywhere on the floor trying to find one body but nothing... Does anyone have any ideas? Could they have made it to another part in my house??? I don't have any fish in my tank that eat shrimp.

Thanks
Jeff