Need to put them in QT first, where they can be trained to take frozen mysis first, and then later dried foods. If you put them into the display tank right away, it is much harder to get them to eat, because of the other fish grabbing all the food and scaring off the Copperband. Here is a vid how I got them to eat dry food. This was back a few years ago.
https://www.youtube.com/watch?v=1fQjAZjafxM