If you are not breeding the feeders, raising them to the appropriate size and then using them...I wouldn't do it. Even buying feeders and keeping them in a tank for a few weeks would make me pause.
Feeders suck. Raw seafood with shell like shrimp...or other seafood like scallops work great. They also sell frozen silver sides. INvariably clean water and a varied diet given to healthy fish will give you best coloration.