I feed Dobby fruit blend Zupreem pellets and he likes most of the colors. I fed my other Maxis the same plus fruit blend nutri berries and whatever fruits and veggies they liked plus he steals some of our food that's reasonably OK for him.
The main thing is find something he'll actually eat as healthy wont do any good if he won't touch it.
If you have something great you want him to try make a big deal of how much you like it and he'll probably get curious about it and want it himself. They love to share dinner time and food with their flock.