Bullheads actually come in a variety of types.
There are 6 types known in North America. But the main 3 is the Black Bullhead,The Yellow Bullhead and The Brown Bullhead.
For the record the other 3 are called; The Flat,The Snail and The Spotted Bullheads. The latter three rarely if ever exceed 12".

Black Bullhead=Record 1987 8lbs 15OZ
Yellow Bullhead=Record 1989 4lb 50z
Brown Bullhead =Record 1991 6lb 2oz(Texas doesnt have Spotted Bullhead.

Now Madtoms....26 of of our 42 species of catfish are actually "Madtoms" little catfish less than 4 inches and inhabit the eastern 2/3rds of the U.S.

Sometimes I wonder if the tiny little catfish Im catching 2-3" long in my shad/bait nets are young game catfish species or Madtoms.
Darn lil guys shore do stick in your nets.

a.k.a. yellow & black bullheads...Not what you
want in your pond, they will take over...

easiest way to tell difference is the tail just look at the mud pic then channel, channel cat has a V shape mud is straight real noticeable

Also Black bull heads have a distinctive light colored "bar" running across just above the tail itself. Channels do not.

Dont for get how good of bait these smaller Bullheads are supposed to be and they live along time. One of the few, as we used to say as kids,that "you could carry around in a shirt pocket for half a day and still be alive".