I've heard other people say that before but when I fed the discus Hans cobalt flake that Hans included with my fish they ate everything. I'm sure they'll come around eventually. The blue flakes are supposed to be loaded with probiotics and vitamins so they probably taste bad lol. I've had the best luck with the super beef heart flake with progrowth from Bill at inlandempirediscus.com My fish go absolutely nuts for that stuff which is very unusual for discus to react that way to flake food. It's especially interesting with my discus because I feed them Al's biopigment plus FDBW cubes, super beef heart flake, Hikari bio-gold pellets, my frozen seafood mix with nori powder/progrowth/promore/lysine, Al's Planktoplus Discus Gold pellets, and an occasional hikari algae wafer disc so my fish have a very wide variety in their diet but the flakes are one of their favorites.