I was once feeding corn on a small river for barbel but instead had a group of 8 or 10 brown and rainbow trout feeding avidly.
I caught one and as I played it I threw in some more grains and watched as the rest of the fish kept feeding whilst their brother swam frantically amongst them.
I unhooked the trout (about 12oz) and slipped it back into the river, it swam straight back to the others and began feeding on corn again.
So yes, they do eat corn.