Chapter 1: The Oldest Aquarium Fish

The world’s oldest aquarium fish may actually be even older than its recorded age. Born prior to World War II, this remarkable creature captivates biologists not just with its age, but also due to its unique anatomy, possessing lungs alongside gills. Sadly, it faces the threat of extinction.

For centuries, humanity has been fascinated by the quest for longevity. Interestingly, animals hold the key to this mystery, not through any hidden wisdom but rather through their inherent biological traits. Numerous species can live over a century, while some organisms boast lifespans that stretch into the thousands of years. Indeed, the animal kingdom is home to several beings that are deemed biologically immortal.

When discussing longevity, Jonathan, a giant tortoise residing on Saint Helena Island near West Africa, takes the crown as the oldest land animal at 190 years old. This venerable tortoise was alive before the invention of the light bulb, with his age confirmed through a photograph from the 1880s.

Another fascinating example is Methuselah, an Australian lungfish hailing from the subclass Dipnoi. Named after the biblical figure reputed to have lived for 969 years, Methuselah was brought to the Steinhart Aquarium in San Francisco in November 1938, amidst the growing tensions of another global conflict and just after the release of Disney's “Snow White and the Seven Dwarfs.” While over 230 other fish accompanied him, Methuselah remains the sole survivor, now recognized as the oldest living aquarium fish.

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

This video introduces you to Methuselah, highlighting his incredible journey and significance in the aquarium world.

New genetic analyses of Methuselah's DNA suggest he may not be 84 years old, as previously thought, but rather 101. His age remained a mystery since his arrival in San Francisco, as scientists in the late 1930s lacked the means to ascertain it. Thanks to modern technology, a minuscule sample from a fin—less than half a centimeter—has provided clarity.

“Uncovering accurate information about her age is tremendously thrilling,” notes Charles Delbeek, curator of aquarium projects at the Steinhart Aquarium. “Methuselah serves as a vital ambassador for her species, inspiring and educating visitors globally. Her influence extends beyond just captivating aquarium-goers; sharing our living collection with researchers worldwide enhances our understanding of biological diversity crucial for species survival and evolution.”

The Unique Biology of Two-Lunged Fish

Research into two-lunged fish across various ages offers insights into their longevity. This year, examinations included not only Methuselah's scale fragment but also 32 additional Dipnoi specimens from the USA and Australia, the oldest of which were 50 and 54 years old. Their remarkable lifespan is not their only defining trait.

Dipnoi, unlike other fish, possess one or two lungs in addition to gills. Australian lungfish are known to surface for air when water quality declines or during drought conditions. Unfortunately, this species is classified as endangered by the International Union for Conservation of Nature, facing threats from pollution, invasive species, and dam construction.

Interestingly, these fish are often referred to as “living fossils,” as they first appeared in the fossil record approximately 380 million years ago. They also possess the largest known genome among organisms, about 14 times the length of the human genome.

The Siege Engines of Ancient Times

The siege engines that plagued ancient cities were a remarkable feat of engineering. The siege of Troy, for instance, was expected to last nine years, yet the Achaeans sought to expedite their efforts.

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