Agreed. By offering many choices, the fish will soon recognize that what you are offering is food and then perhaps you can slip the pellets in. Maybe try mixing pellets with garlic.
I have plenty of guppies that I could feed my dempsey but I know once they are offered ,it will be increasingly more difficult to get him to try the pellets. I keep trying and he keeps refusing but I am hopeful. At least he is eating the other foods I mentioned.