Hm....If you don't soak the worms first, they can puff up a bit after they are eaten. So that may be more of a problem than the flakes. Maybe fasting could also help. I skip Sunday feedings to make sure their digestive systems aren't over taxed. If your fish is snubbing pellets, it could be the brand. I notice my fish will only eat Hikari or New Life Spectrum. I would suggest trying New Life if you are near the end of your current food.