I have a BTA and he eats just about anything. I buy fresh fish from the grocery store, swordtail, tuna, talapia. I take it home and cut it up into small fish size sections and feed it to him using aquarium tongs. I put the food near his mouth and he grabs it and eats it. Poops it out later at night, but he does eat it.
I tried tonight to make a mash of several different kinds of raw fish meat and processed it all in a food processor to make a this paste. Offered him a chunk and made a mess. He didn't eat it, he grabbed it and released it. And the loose particles from the mushy mash got in the tank water. I won't do that again.
Just simple chucks of raw fish meat of varied kinds. Shrimp, tuna, etc.