My Amano shrimp are the bullies of the tank. They go where they want when they want and will fight off even my biggest fish to get to food. I have some pretty big Roselin Barbs. I've seen them yank food right out of another fishes mouth and swim away with it.
Give them time they will come out.
I have 11 of them in a community tank. I wonder if they are less shy in numbers than if you just have one or two.
I agree with Jadenlea, My amanos are absolute thiefs. When I feed my fish I normally drop in a couple of bits of algae wafers or shrimp pellets for all of my bottom feeders, but the amanos are always trying to steal it away from them. I want the amanos to clean up on any algae not eat the fish food.