The Australian lungfish named Granddad has died at his home in Chicago’s Shedd Aquarium. The aquarium says more than 104 million guests saw him during his eight decades housed at the aquarium.

Shedd Aquarium’s web editor, Karen Furnweger, posted a tribute to Granddad, recounting his life and history on the aquarium’s website:

"The last living link with Shedd’s earliest history was broken Sunday, Feb. 5, when our animal care team made the difficult decision to euthanize Granddad, the world-famous Australian lungfish, after a rapid decline in his health. Granddad had graced Shedd’s original galleries since 1933.

"Granddad was not only Shedd’s longest-lived resident but also the oldest fish in any public zoo or aquarium in the world. And he was the last standing (or swimming) among Chicago’s beloved trio of ancient animals, which also included a dwarf African crocodile, R1, who lived at Lincoln Park Zoo from 1930 to 2010, and Brookfield Zoo’s 83-year-old Major Mitchell’s cockatoo, Cookie, who died in August of last year.

"In tribute to Granddad, President and CEO Bridget Coughlin, Ph.D., said, 'It is incredible to know that more than 104 million guests had the opportunity to see Granddad in our care and learn about his unique species over eight decades.' She noted that the famously sedentary fish 'sparked curiosity, excitement and wonder among guests of all ages.' ”

Web editor Karen Furnweger reports: "Granddad led an easygoing life, typical of his species. Australian lungfish are native to the Mary and Burnett Rivers in Queensland, in the northeastern corner of the continent, where they prefer deep pools within free-flowing waters. They possess a single primitive lung in addition to gills, enabling them to survive when waters become stagnant and oxygen-depleted during seasonal droughts. Australian lungfish cannot, however, survive on air breathing alone.

"Granddad delighted guests when several times an hour he would slowly rise from his apparent torpor at the bottom of the habitat, slowly flap his large pectoral and pelvic fins, and slurp air at the surface. Behind the scenes, aquarists in the vicinity were occasionally startled by the long, loud snorts the fish made as he breathed.

"Although we couldn’t pinpoint Granddad’s age, Australian lungfish can reach the century mark, and we think he was close to it. Granddad and a female were full-grown adults when they were collected for Shedd in ’33 by the Taronga Zoo and Aquarium in Sydney, Australia. In anticipation of overflow crowds from the soon-to-open Century of Progress International Exposition just south of Shedd, aquarium director Walter Chute had written to the director of the Sydney aquarium with a wish list of fresh- and saltwater species. 'We are, of course, particularly desirous of securing one or two specimens of Neoceratodus forsteri,' he wrote, using the lungfish’s scientific name."

DISCOVER OUR FAVORITE SMALL FISH AND MARINE ANIMALS IN THE OCEAN

In the tribute on Shedd's website, web editor Karen Furnweger writes: "From Sydney and Chicago newspaper accounts, the pair of lungfish and 600 other aquatic animals, tended around the clock by members of Shedd’s collecting team, steamed out of Sydney’s harbor on May 6, 1933, stopped briefly in Hawaii where the rest of the collecting crew loaded several hundred Pacific fishes, and arrived in Los Angeles on May 23. The precious cargo was transferred to Shedd’s life-support-outfitted railroad car, the Nautilus, for the three-day journey to Chicago. After the 9,000-mile trip, the animals were most likely in their new habitats for the May 27 opening of the fair. The two lungfish were the first of their kind on display in the United States."

Read the aquarium’s press release here.

"For decades Granddad and his mate, who died in 1980, occupied a stacked-rock habitat at the end of what was called Gallery 6, now the Rivers gallery. In 1992, Granddad was taken off exhibit while his space was incorporated into the double Southeast Asian Streams habitat. During his nearly two-year hiatus in a reserve area, staff members repeatedly assured anxious aquarium members and other guests that their favorite lungfish was doing fine and would be back on view in a spacious new habitat re-creating a Queensland riverbank ecosystem. The exhibit opened in May 1994 with Granddad and five 8- to 10-year-old lungfish donated by the Australian government.

"Granddad was arguably Australia’s most famous expat. In 2013, the Australian consul general joined aquarium staff members, volunteers, guests and the media to fete the venerable fish on his 80th anniversary at Shedd and presented him with a proclamation recognizing 'the tremendous relationship between the John G. Shedd Aquarium and the Government of Australia.'

"Late last week, however, Granddad lost interest in his food, and he was monitored closely by members of the Fishes and Animal Health teams. When a physical examination showed that the geriatric fish’s organs were failing and his quality of life was slipping away, our Animal Health team made the humane decision to euthanize him. A full necropsy conducted in partnership with pathologists from the University of Illinois College of Veterinary Medicine confirmed the fish’s age-related deterioration. The forthcoming report should include an examination of his otoliths, bones in the ear that added layers like tree rings throughout his life, to reveal exactly how old Granddad was."

Lungfish have existed over 380 million years, according to fossil data, and have remained virtually unchanged for over 100 million years. They are estimated to live up to 100 years old and are a protected species in Australia.