Here is a nice article I found on Planaria.
Near the end of the article it states:
"Warning - Research carried out by Tim Henshaw at Bolton Museum (Lancashire, U.K.) indicates that Planaria carry a toxin on their surface. This toxin is particularly potent towards any species of shrimp and glass shrimp."
Maybe this is why the shrimp seem to jump when they come in contact with Planaria. I really need to find something that will take care of these guys in my shrimp tanks! I have read that Fluke tabs will work but I'm not sure how they will affect the shrimp. I may have to try it on the cherry shrimp tank and see what happens. If the Cherries don't survive the Fluke tabs I can get some more fairly inexpensively. Hopefully Wayne or Rob still have a nice breeding colony of them.
I think I finally know what has been happening to all of my shrimp fry for the past year or so