San Francisco-based Methuselah is at 90 years old believed to be the oldest aquarium-based fish in the world.
The veteran tank-dweller likes to eat fresh figs, get belly rubs and is named after the Biblical figure, Noah's grandfather, who 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 four-foot-long, 40lb Australian lungfish that was brought to the San Francisco museum in 1938 from Australia.
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 Academy and the fish's keeper.
Methuselah's caretakers believe the fish is female, although it is difficult to determine the species' sex without a risky blood draw.
The Academy plans to send a tiny sample of her fin to researchers in Australia, who will try to confirm the sex and figure out the fish's exact age.
Mr Jan says Methuselah likes getting rubbed on her back and belly 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 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.
The Academy has two other Australian lungfish that are younger, both believed to be in their 40s or 50s, Mr Jan said.
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'll get a replacement once Methuselah passes away.
"We just give her the best possible care we can provide, and hopefully she thrives," Mr Jan said.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here