Amanos shouldn't eat Cherry shrimp, however in the past i have had a few male Amanos, and they have the knack to almost smell impending death. As Taffy Apple said, they will stalk a weaker species whether it be fish or other shrimp that are dying or close to death. I have observed this a few time over the years in my tanks. I remember a few years introducing a Dwarf Gourami (a weak species at the best of times!) to my 60ltr and i thought everything was good, and this Amano i had was stalking him around the tank for a few hours, in the morning the Amano was just finishing his dinner. I currently have about 6 Amanos and 10 Cherries in my tank and theres no problem.
BTW you need to be adding more than 1 of each, but thats been covered ^^^