Tokugawa Tunabread was a former shogun of Little Tokyo, referenced in the episode "Underground, Underwater, Undercooked". According to the english narrator, Tunabread was notorious for his obsession with seafood. Particularly fond of freshly caught fish, he refused to eat anything but seafood. His obsession eventually became so fanatical that he issued a royal decree, which forbade his subjects from eating his favorite food. As the people of Little Tokyo began to complain, Tunabread issued even more stringent laws; forbidding the catching of fish without a royal license or keeping fish as pets. This forced the citizens of Little Tokyo to return their fish to the sea or risk the wrath of Tunabread's "Fish Police". Eventually, all of the fish in the kingdom were rounded up and locked away in a giant water-filled vault deep beneath the city. Some time later, Tunabread was, ironically, eaten by a giant grouper after falling overboard while on a fishing trip.
Tunabread's vault was sealed shortly after his death and remained forgotten until rediscovered by Bad Bird many years later. Bad Bird had uncovered an ancient map in the royal library which revealed the location of the vault and that it contained a fortune in, "gold ____". This second word had been scratched off the map's instructions. This led Bad Bird to believe that the vault literally held a fortune in gold, only to discover to his horror upon opening the vault that the missing word was, in fact, "Fish".