Feeding habits

Until Saturday I did feed my fishes with frozen and live food and as well with pellets every day, but my largest Festae did not eat pellets at all. I was not concerned about his feeding habits until Friday when my colleague told me I should adopt it to dry pellets as main food and use frozen and live food only as supplementary food. He explain me that dry food should bring me better coloured fishes and that my fishes could actually experience some healthy issues by time if I don't change its feeding habit. So I took decision to feed my fishes with dry pellets every day and twice a week with frozen and live food (but only after I adopt fishes to dry pellets). I start adopting fishes to dry pellets on Saturday and all of my fishes adopt to it already with no problems except my largest Festae who refuse to eat pellets like he did before. Sometime he get close to the pellet - it is like he would smell it - and turn away from it. So I got concerned that I could actually starve him till death while adopting him to dry pellets - Should I be concerned already? When should I get concerned? Should I give some frozen food time to time while I adopting him to dry food as main food before I starve him till death - how long should I let him starving before giving him frozen/live food or how often should I give them frozen/live food?
I am looking for advice how to adopt largest Festae to new diet? I would appreciate any advice, thanks.