I wouldnt do meats or chicken. try fish shrimp or squid chunks. my fish love all of these and its really not that expensive. my oscar and pbass loves smelt and silversides
if you feed them a good and varied diet, every meal is a treat so you don't need to give them offbeat foods.
I would avoid ham under any circumstances, there's a lot of salt and nitrites in it.
try some freeze dried crickets. a lot of fish eat insects, but I'm not aware of their inclusion in any prepared food.