I threw in some beef heart for my endlicherri, but the tiger fish snatched it before the bichir could. Turns out that he loves the stuff, BUT is beef heart a good thing for an ATF to be eating???
In small ammounts it wont do any harm but as fish have a hard time digesting mammalian proteins it is not good to use as a regular standard food for any fish. It would be better to stick to foods from aquatic habbitats such as clams, mussels, fish and shrimp/prawns.