In the spirit of imitating nature to the best of my ability, I have excluded most terrestrial vertebrate meat from my fish diets. However, my Oscar does enjoy the occasional tiny piece of boiled chicken. Perhaps once every two months or so. About as often as an Oscar might be lucky enough to stumble across a dead rodent or bird. Otherwise, worms, insects and algae are the foundation of most good fish diets. I use pellets 80% of the time because of cost but I would much rather feed my fish tons of live insects and such. But not mammal meat. It doesn't make sense. To me, based on my philosophy. But apparently somebody raises discus on a diet exclusively comprised of beef heart. Draw your own conclusions. My mind is made up.