As said, dont apply meds if your not sure if there's anything wrong. Your tank parameters are good so keep it up.
I've never owned an Asian Aro, but I can't imagine a 6" turning away bloodworms, so give that a shot. In the long term, I think pellets are best as a staple. When training, I always start with a few pellets to start. Then follow by something I know they like such as bloodworms, mealworms and/or small crickets.
Be patient and eventually it should take the pellets and not spit out.