from all the people who have kept them, of course initially just live worms, and guppies, then you mix in small bits and pieces of cut fish or shrimp, use a power head to blow up the food, so they will chase after it. also good to use some tiny cichlids or something that will eat pellets to train them. monkey see, monkey do, and soon they will learn to eat anything.
massivore has been shown to make them grow very big and very fast. all the datnoids out there that are over 12-15" like NTT or NGT, have all been raised on massivore, the food must contain something in it that makes them grow. and these get that size in less than 2 years usually, which cannot be achieved by normal cut fish and shrimp