I used to stock a small pond behind some apartments back when , put my left over shiners in it ,some sunfish and some bass , there were bullheads already in it too , they would all lose their minds when I showed up with a slice of whitebread .
the water would just boil with fish within a second or so of the bread hitting the water .
white bread was my go to bait when i carp ketched as a kid , chummed in with corn and a doughy ball of white bread on a single hook no sinker , just deadly and fun as heck too
it is very similar to why in the heck are the fish losing their minds on whole kernel corn , some used to say it resembled fish eggs , but i never bought that excuse , it is more likely the sugar content in the bread and corn and the scent it leaves in the water