Use a high quality pellet as a staple. The other items can be given as a "treat".
I had (years ago before I knew better) a Midas that I fed exclusively beef heart. He was always eager for it and seemed to have no issues until he got hole in the head. Granted my tank was too small and I did not keep up on the water in the right ways but the diet was another factor I will add to the list. I do not believe he was getting the things he needed to keep him healthy.
I said size of tank because it was not adequate to house the fish to begin with. So a limited amount of water (29g) and a large fish (12") can make it difficult to maintain proper water conditions. It was a contributing factor to the problem.