i recently ran out of the food that i normally feed them(FD bloodworms) so they got starved for a few days till i got some flakes(also colorful i think that might have helped) and i tried it and my new angelfish came right up to me and started eating it. and today my older angelfish started to do it to. so in short:get them use to a colorful food, starve them for a few days, and grab some of the food and stick you hand in(slowly though, dont scare the fish)