if you really want them to eat what you buy just starve them for a day or two and then the first thing you put in should be the new food, usually fish are so opportunistic they will eat whatever is available. i had to do that when introducing a new food to their variety.....i also alternate what i feed them first so they don't get picky... good luck.....and mabe you should check out some beefheart recipes alot of ppl add shrimp and other vits like spirulina or many others. and you may wanna freeze that stuff so it don't stink up the whole house/fridge