Cherry barbs are great fish. They are very easy to feed, will likely take pretty much any flake or small pellet food offered. I like something slow sinking, though they will hunt at the substrate.
Most likely, they will get used to the light, but this is really natural behavior. Daylight means predators at the surface, so they will tend to hide in the shadows. You can add plants, floating or large leaved, like an anubias, to provide more places at the top for them to hang out.