What kind of fish food is best for my goldfish?

Sinking pellets are by far better for goldfish. They also aren't as messy as flake. Swim bladder disease is usually caused from a goldfish swallowing air while trying to eat floating foods. You can also feed them fresh orange slices, peas, romaine lettuce, and zucchini...as far as fresh foods go. Bloodworms, brine shrimp, mysis shrimp, and blackworms are also good to provide.