Nice fish, and a smart move on the part of the seller. He gained a lot of brownie points with a new customer, using a fish that likely nobody would have been satisfied to pay for otherwise.
How does the little one get around without pectorals? Fish rely on their pectorals for much of their maneuverability and control, and bichirs seem to also use them somewhat for basic locomotion. I sorta kinda tend to think that the seller may have kept this one long enough to satisfy himself that those fins are not growing back. The fish seems well-fed and healthy otherwise.
But, hey, nowadays the more misshapen the fish the better; you might be able to start a new trend. Who would bother to buy a short-body or platinum or longfin bichir...when they can get one that has been circumcised!