Common Mynah eating issues

Hi Guys, I am new to the forum cause I need advice. I have a Common Mynah whom is 2years old. He used to love papaya, apple, almond nuts and cucumbers. For the passed 2 weeks he does not want to eat any of it, only dog pellets.. should I be worried? Or do you know of anything else I can try to feed him?
He is not losing weight or anything which is good.. buy still worried that his loved food is no longer wanted..
Please help.