That is the madtom that you are not supposed to get poked by. I have never been stung by one, only stonecats and mountains, but I have heard some bad stories to include heart palpitations and pain all the way to the shoulder. Then apparently some people have hardly any reaction from them.
Cool find, much more interesting than bullheads anyway.
Interesting that you mention that. I have caught stonecats several times and held them like I'm pictured holding this guy and haven't yet been poked by one. This guy got me twice in rapid succession. Once in the pinky then in the ring finger. I did get pain going up the arm from it. I don't know if it really helped or not, but I poured some isopropanol and then some hydrogen peroxide over the puncture wounds and within a few minutes couldn't even tell that the pinky had been stuck. I still felt a sensation in the ring finger and arm for about another half an hour, but it wasn't what I'd call painful.
One thing that surprised me was how much my fingers bled considering how tiny the actual puncture wounds were. Not that I lost massive amounts of blood or anything, just that small finger pricks usually quit bleeding after a couple drops of blood. These bled for a few minutes. I suppose that might be part of the reason the pain diminished too.