I've used many thinking certain food would enhance color and head development. I went as far as making my own blend...grinding up grand sumo, hikari, spirulina flakes, tetra flakes, freeze dried bloodworms & shrimp. Added water to form a paste and rolled up my own pellets. Even experimented with peas, spinach and beef hearts. What a mess! From my personal experiment, I concluded that it became such a chore, it took me away from the hobby. In all honesty, most pellets out there are good imo. Hikari and NLS are up there on my list. However much my flowerhorns love frozen bloodworms, I swear never to it to them ever again....I believe they can transmit parasites. Considering the effort I put into the care of these valuable fish, when they started falling ill, the only source came down to the frozen bloodworms. I found the safest treat was freeze dried bloodworms & shrimps.
Ultimately, a good quality staple diet along with pristine water will keep them happy.