Maybe the move was just too stressful for him? Being wild caught...they just aren't accustomed to having human's in their faces like the tank raised fry are...and some fish are just more resiliant then others too, he could have had something stress him out before he got to you and it just all added up on him...you just never know.
Stress lowers their immune system, and being wild caught their nerves are going to be worse then a tank raised fish anyways....so there are tons of factors that could have affected him adversly.
I know that alot of people try to keep their brim, catfish, and baby bass they catch in the lakes/rivers and 90% of them die...from being stressed out (from being caught and transported, then being in full view of people) and then getting sick and die.
Maybe when people get wild caught fish they should keep the tank covered and in an out of the way place, where noises and vibrations are minimal, and gradually introduce themselves and human noises over a period of time, extending each viewing time longer and longer until they get relatively accustomed to seeing people and hearing all the noises we make.
Sorry about your fish though....really sucks..but atleast you still have a pair left though....good luck with those!