World’s oldest captive fish euthanized by Chicago aquarium

A 90-year-old Australian lungfish called Grandad, believed to be the longest-living fish in a zoological environment, has been euthanized in a Chicago aquarium.

The lungfish was euthanized Sunday by an animal care team at the Shedd Aquarium in Chicago, where he has lived since they acquired him in 1933. Grandad was said to be in his mid-90s.

The team said they reached the “difficult decision” to end Grandad’s life, due to his rapidly declining health, in a statement shared on Monday.

“Grandad was not only Shedd’s longest-lived resident but also the oldest fish in any public zoo or aquarium in the world,” the statement read.

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Grandad was seen by more than 104 million guests during his time at the aquarium and although his exact age is unknown, Australian lungfish can reach age 100 and the team “think he was close to it.”

Grandad, who was “arguably Australia’s most famous expat,” was a fully grown adult when he was collected by Shedd in 1933 from Taronga Zoo and Aquarium in Sydney, Australia.