For more than eight decades, an Australian lungfish named Granddad resided at Chicago's Shedd Aquarium. The beloved fish made the journey from Australia by steamboat and train to dazzle attendees of the legendary 1933 World's Fair. Since then, the aquarium estimates some 104 million guests have seen the famous lungfish. Granddad's long life has come to an end, after he was euthanized "due to a rapid decline in quality of life associated with old age," according to the aquarium . Granddad was the "longest-lived of any fish in a zoological setting in the world," according to the aquarium. A spokesman for the Association of Zoos and Aquariums, Rob Vernon, tells The Associated Press that "the nonprofit group is unaware of any older fish kept by a zoo or aquarium that it accredits in the U.S. or eight other countries." But Grandad is being fondly remembered for far more than simply his impressive age, which the aquarium estimates at close to 100 years . "For a fish who spent much of his