Natural food is simply unprocessed food. The fanatics at the gab (link per dkpate) would make their own using gelatin, fish, veggie, etc. But really, a simpler way is to feed a good quality pellet (like Hikari) & to supplement with fresh food a few times a week. <Pellets are more nutrient dense than flakes & also tend to give less gut problems in fancies.>
For the natural food, I use: Frozen peas - microwave, then shelled & chopped. Slices of zuccchni or cucumbers - blanched. Bits of ornages. Chopped up cooked cocktail shrimps. <That is my main "animal" treat ... other people use earthworms, daphnia, etc. but shrimp is easy & reasonably cheap.>
