QB dont get very big however there almost indestingwishable(sp?) cousin the river carpsucker gets pretty darn big, over 24in. also if it had a red tail and was skinny(carpsuckers have a humped back) it would have been either a shorthead redhorse or a river redhorse, im guessing a river redhorse, they get quite large up over 30in and they are not very common, so that would be a good shot, i have snaged them this time of year before.
i wouldn't worry about it being one of the invasives or one of the endangered ones, the silver and bighead carps have not been found in the ohio strech of the ohio river to my knowelege, and i haven't seen them above the falls of the ohio. there arn't any snakeheads yet.., there are the occasional phirana, pacu, grass carp, or tilapia. as for the endangered fish there is the blue sucker but if you catch one you will know it, they have a rediculous dorsal fin and they are...blue, like blue jeans. most of the other endangereds we have are all minnows, darters, and madtoms, so you wont likely catch them
looking back on your post it is definantly a redhorse, the description is almost perfect, they have bright red caudal(tail) fins and very small mouths with pointed dorsals