The longest-living fish in a zoological setting, a lungfish known as Granddad acquired by the Shedd Aquarium in Chicago in 1933, has been euthanized after suffering failing health well in his mid-90s, aquarium officials said on Monday.

Granddad, who came to Shedd from Australia in anticipation of the 1933-34 Chicago World's Fair, was seen by more than 104 million people during his time in Chicago, aquarium president Bridget Coughlin said in a statement announcing his death.