I think in the absence of other foods, he will take to tilapia and any other scraps if that is all he will have to go by. May take a little time but I think he will. The bigger these guys are, the less fussy they tend to get about foods.
I'd be a little concerned if 100% of his diet was just flesh/tilapia fillet scraps. But I am sure you'll find a way to diversify his diet a bit so he gets the nutrients he needs. I have no clue if it may or may not hurt him to be on such a protein-rich, almost exclusive diet with no plant matter at all. I guess time will show.