Methuselah has been living at the Steinhart Aquarium since 1938 (Credit: CC-BY-SA-2.0)

Methuselah, a female Australian lungfish at San Francisco's Steinhart Aquarium, has always been a favorite with locals. But she has achieved global fame since September 2023, after scientists announced that she was at least 93 years old, making Methuselah the world's oldest living aquarium fish. The title was previously held by Grandad, an Australian lungfish who lived at Chicago's Shedd Aquarium. He was believed to be between 109 and 115 years old when he died in 2017.

Methuselah is named after the oldest person mentioned in the Hebrew Bible. He purportedly lived for 969 years! She arrived at the aquarium aboard a steamship in 1938. True to her name, she has outlived the 231 other fish that came with her from Fiji and Australia. Based on the arrival date, the aquarium biologists knew that the 4.5-foot-long, 40-pound lungfish was at least 85 years old. But until recently, they could not get a more precise estimate of her age.

A new study estimates Methuselah is between 93 and 101 years old (Credit: CC-BY-SA-2.0)

The recent study was led by Australian scientists Dr. Ben Mayne and Dr. David Roberts. The researchers took tiny samples from Methuselah and 30 other aquarium lungfish. They then extracted the DNA and used special tools to determine the age of each specimen. For younger fish, the technique provides an exact number. However, for older fish, it can give a range of dates. Based on the data, the scientists concluded that Methuselah was between 93 and 101 years old.

"Although we know Methuselah came to us in the late 1930s, 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," says the aquarium's assistant curator, Charles Delbeek.

Methuselah is currently the world's oldest living aquarium fish (Credit: CC-BY-SA-2.0)

The Australian lungfish is one of six air-breathing lungfish species worldwide. The marine animals typically use their gills to obtain oxygen. But during dry periods, the fish can live out of water for several days by breathing air as long as the surface of their skin remains moist. The species was listed as endangered by the IUCN in 2019. Thankfully, due to timely protection measures, their numbers appear to have stabilized since.