Methuselah, the World’s Oldest Living Aquarium Fish, Could Be More Than 100

Using a new and noninvasive technique, researchers analyzed the DNA of 33 lungfish in institutions across the U.S. and Australia to determine their ages

An Australian lungfish
Methuselah, the oldest fish living in an aquarium, was transported to California in 1938. Gayle Laird

In November 1938, an Australian lungfish named Methuselah arrived at San Francisco’s Steinhart Aquarium aboard an ocean liner. At that time, the United States was just recovering from the Great Depression. Germany, under the rule of Adolf Hitler, had recently annexed Austria. One year earlier, the first animated feature film released by Walt Disney, Snow White and the Seven Dwarfs, premiered in Los Angeles. 

Methuselah, named after the biblical figure who died at 969 years old, far outlived the 231 other fish from Fiji and Australia that arrived in San Francisco with her. And she’s still swimming at the aquarium today, located at the California Academy of Sciences. 

In 2017, she unofficially assumed the title of the world’s oldest living aquarium fish, writes the New York Times’ Soumya Karlamangla. But now, a new DNA analysis suggests she might be even more aged than previously thought. The research, which will be published later this year, estimated Methuselah has lived about 92 years, though she could be as old as 101. Her previous estimated age was 84. 

“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,” Charles Delbeek, curator of aquarium projects at Steinhart Aquarium, says in a statement. “Methuselah is an important ambassador for her species, helping to educate and stoke curiosity in visitors from all over the world. But her impact goes beyond delighting guests at the aquarium: Making our living collection available to researchers across the world helps further our understanding of biodiversity and what species need to survive and thrive.”

Meet Methuselah, the world's oldest living aquarium fish at Academy of Sciences

The scientists also took samples from 32 other lungfish in institutions across the U.S. and Australia, including the academy’s two other lungfish (ages 50 and 54), to create a “catalog of living lungfish,” per the statement. Delbeek tells ABC7 this information could help researchers with conservation efforts. 

Previously, efforts to determine the age of lungfish were a lot more invasive—and potentially damaging to the animals. Scientists would have to examine the fish’s ear bones or remove entire scales. With this new method, the researchers collected a tiny sample of the fin—less than half a centimeter long and wide. They looked for specific molecules sticking to the animal’s DNA known as “methyl groups,” which increase with age, writes Ellen Phiddian for Cosmos. By studying lungfish of various ages—especially old ones—the team could fine-tune its lungfish-aging method and learn more about the species’ longevity.

The Australian lungfish (Neoceratodus forsteri), also called the Queensland lungfish, is one of six lungfish species. These ancient animals are sometimes referred to as “living fossils,” because they first showed up on the fossil record about 380 million years ago. Australian lungfish have the largest known genome of any animal, per Cosmos—about 14 times longer than even humans’. 

Unlike other fish species, lungfish have one or two lungs in addition to their gills. Normally, Australian lungfish use their gills to obtain oxygen, but when water quality changes or when streams go through dry periods, they can come to the surface to breathe air. The species is listed as endangered on the International Union for Conservation of Nature’s Red List due to threats from pollution, invasive species and dams.

Over her many years at Steinhart Aquarium, Methuselah has built a reputation for her “charming personality and penchant for belly rubs,” per the statement. 

“She’s a pretty content, happy fish, I’m going to say,” Brenda Melton, the aquarium’s director of animal care and well-being, tells the Times. “She’s been around a long time. She’s seen more than any of us at Steinhart Aquarium. We’re lucky to have her.”

Get the latest stories in your inbox every weekday.