The two fish look quite similar. The condition is not an infection but a genetic condition that shows up in older mature bass and catfish. It is not transferable to humans and humans cannot get the condition. Fish with this condition are safe to eat as long as they are cooked to at least 145 degrees. The condition results from an overdose of Melanin in the skin, received from continued exposure to sunlight. The clear water on Lake Norman creates a situation where fish can develop the condition more easily than in waters that are less clear or even murky.
Since fish almost never like exposure to the sun. I decided that there is another condition that the bass have that might lend itself to this condition. it is call "stupid bass syndrome."