Meet Methuselah, the oldest living, walking aquarium fish

90-year-old Australian lungfish lives in the lap pool of luxury in San Francisco

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  Methuselah, an Australian lungfish that was brought to the California Academy of Sciences in 1938 from Australia, swims in its tank in San Francisco, California. AP

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  Methuselah, an Australian lungfish that was brought to the California Academy of Sciences in 1938 from Australia, rests at the bottom of its tank in San Francisco, California. AP

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  Senior biologist Allan Jan holds Methuselah. AP

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  Allan Jan feeds Methuselah, the oldest living fish in captivity in the US. AP

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  Allan Jan feeds Methuselah. AP

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  Visitors look at Methuselah the Australian lungfish. AP

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  Methuselah is the oldest living fish in captivity in the US. AP

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  Methuselah is suspected to be about 90 years old. AP

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  Methuselah lives at the Steinhart Aquarium at the California Academy of Sciences in Golden Gate Park in San Francisco, California. Methuselah is the oldest living fish in captivity in the US. AP

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  The primitive freshwater fish can breath on land and in water. Methuselah came to San Francisco on a steamship from Queensland, Australia, in 1938 and the details of where she was was collected or who supplied her to the Aquarium are unknown. Biologists are unsure whether Methuselah is a male or female. EPA

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  Methuselah is the oldest living fish in captivity in the US and can walk on land. EPA

Meet Methuselah, the fish that likes to eat fresh figs, get belly rubs and is believed to be the oldest living aquarium fish in the world.

In the Bible, Methuselah was Noah’s grandfather and was said to have lived to be 969 years old. Methuselah the fish is not quite that ancient, but biologists at the California Academy of Sciences believe it is about 90 years old, with no known living peers.

Methuselah is a 1.2-metre, 18.1-kilogram Australian lungfish that was brought to the San Francisco museum in 1938 from Australia. Most varieties of lungfish can "walk" by using their fins.

A primitive species with lungs and gills, Australian lungfish are believed to be the evolutionary link between fish and amphibians.

No stranger to publicity, Methuselah’s first appearance in The San Francisco Chronicle was in 1947: “These strange creatures — with green scales looking like fresh artichoke leaves — are known to scientists as a possible ‘missing link’ between terrestrial and aquatic animals.”

Until a few years ago, the oldest Australian lungfish was at the Shedd Aquarium in Chicago. But that fish, named Granddad, died in 2017 at the age of 95.

“By default, Methuselah is the oldest,” said Allan Jan, senior biologist at the California Academy of Sciences and the fish’s keeper.

Methuselah’s caretakers believe the fish is female, although it’s difficult to determine the species’ sex without a risky blood draw. The academy plans to send a tiny sample of fin to researchers in Australia, who will try to confirm the sex and figure out the fish’s exact age.

Methuselah likes figs that are in season and belly rubs. EPA

Mr Jan says Methuselah likes getting back and belly rubs and has a “mellow” personality.

“I tell my volunteers, pretend she’s an underwater puppy, very mellow, gentle, but of course if she gets spooked, she will have sudden bouts of energy. But for the most part she’s just calm,” Mr Jan said.

Methuselah has also developed a taste for seasonal figs.

“She’s a little picky and only likes figs when they are fresh and in season. She won’t eat them when they’re frozen,” said Jeanette Peach, spokeswoman for the California Academy of Sciences.

Organic blackberries, grapes and romaine lettuce are rotated into her daily diet, which also includes a variety of fish, clams, prawns and earthworms, said Charles Delbeek, curator of the museum’s Steinhart Aquarium.

The academy has two other Australian lungfish that are younger. Named after their sizes, “Medium” arrived at the museum in 1952 and “Small” in 1990, both from the Mary River, in Queensland, Australia, said Mr Delbeek.

They weigh about 11kg and 7kg, respectively.

The Australian lungfish is now a threatened species and can no longer be exported from Australian waters, so biologists at the academy say it is unlikely they will be able to find a replacement once Methuselah passes away.

“We just give her the best possible care we can provide, and hopefully she thrives,” Mr Jan said.