Meet Methuselah: The world's oldest known aquarium fish is at least 92, DNA shows

This scaly world-record breaker looks much younger than she is. Or so scientists say.

The approximate age of the oldest-known aquarium fish housed at a San Francisco Bay Area aquarium for the past 85 years is now known, the California Academy of Sciences announced Monday.

Methuselah, a female Australian lungfish tanked at the Steinhart Aquarium in San Francisco, is at least 92 years old, the academy said in a press release.

"Cutting-edge DNA analysis" estimated Methuselah’s age to be nine years older than her previously estimated age of 84. The analysis was led by doctors Ben Mayne of Commonwealth Scientific and Industrial Research, an Australian-based government agency, and David Roberts of Seqwater, also based in Australia.

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The 4-foot long, 40-pound Methuselah, named after the oldest person mentioned in the Bible, first arrived at the aquarium via a Matson Navigation Company shipping liner in 1938, the academy said.

“There was no method for determining her age at that time, so it’s incredibly exciting to get science-based information on her actual age,” Charles Delbeek, the aquarium's curator of aquarium projects, said in a statement. “Methuselah is an important ambassador for her species, helping to educate and stoke curiosity in visitors from all over the world."

Estimating ages for old and ancient fish can be challenging and usually requires invasive or lethal aging methods, including examining ear bones or removing its scales, researchers said.

The new method used to calculate Methuselah's age, the academy said, involved a small tissue sample from a fin without harming the fish.

“For the first time since the Australian lungfish’s discovery in 1870, the DNA age clock we developed offers the ability to predict the maximum age of the species,” Mayne said. “Knowing the ages of fish in a population, including the maximum age, is vital for their management. This tells us just how long a species can survive and reproduce in the wild, which is critical for modeling population viability and reproductive potential."

Another study

Another study led by Mayne and Roberts also sampled 30 other lungfish from six other institutions across the U.S. and Australia "to create a catalog of living lungfish in an effort to advance the accuracy of the previously developed DNA-based age clock for the species."

Included in the catalog are the Steinhart Aquarium's two other lungfish, which are 50 and 54 years old.

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Methuselah may even be older

According to Roberts, Methuselah's age prediction may be further trimmed down as time passes.

“By aging living lungfish from across the world we are creating a library of living lungfish that will enable Dr. Mayne and other researchers ... to continually recalibrate the aging clock as new and older aged samples of lungfish become available," Roberts said.

"This means her actual age could conceivably be over 100, placing her in the rare club of fish centenarians," he said. "While her age prediction will improve over time, she will always live beyond the calibrated age clock, as no other lungfish we know is older than Methuselah."

Natalie Neysa Alund is a senior correspondent for USA TODAY. Reach her at nalund@usatoday.com and follow her on X, the platform formerly known as Twitter @nataliealund.