They can be quite shy, especially after being moved into a new home, or if they are kept together with big and/or aggressive fish that might pester them. They also tend to be less shy if kept in larger numbers. But if the tank is cycled and stable and all the parametres are correct I wouldn't worry. It took quite a long time for my amanos to come out of their shell, so to speak
Make sure they have lots of hiding spaces to make them feel safe, and that filter intake can't suck them up, as that can be a potential danger (especially for babies).