Our Better Nature: Old Fish May Hold the Key to Longer Life

Around age 50, I began to use reading glasses for fine print, and within a few years, for regular-size print, too. These days, long on joint pain and short on memory, it’s clear my “best by” date came and went quite some time ago. While I’d like to stay kicking a while longer, I sure don’t want to live forever, given that aging is a downhill path for all of us.

And yet, from antiquity to modern times, immortality has piqued our interest. Over 4,000 years ago, the Mesopotamian king Gilgamesh is said to have wanted eternal life, or at least a longer one. Alexander the Great purportedly searched for an elixir of youth, and legend has it Spanish explorer Juan Ponce de León quested for a “Fountain of Youth” in present-day Florida in the early 1500s.

The search continues today. In August, 2025, a scientist at the University of Birmingham in England said humans have the potential to live for 20,000 years. But they might “live” even longer thanks to cryonics. Folks who can cough up in excess of $200,000 (which sounds like a major health problem right there) can be frozen at death and revived when there’s a cure for irrational thinking and whatever else killed them.

The Fountain of Youth may be fiction, but a few “lakes of youth” really exist. Research done in the remote Experimental Lakes Area in Canada over the past 58 years has revealed that the lake trout there show no signs of aging. Lake trout are native to cold freshwater lakes in the Northeast and Great Lakes regions, as well as most of Alaska, parts of Montana, and all of Canada below the Arctic. They’ve also been introduced to many places west of the Rockies. Prized as game fish, they can exceed 20 pounds, with Colorado boasting the lake trout world record of 72 pounds, set in 2023.

Although some of the trout in the Experimental Lakes Area are old, they’re biologically as young as ever. In fact, the old fish are apparently better at making babies than the younger adults are. In their 2022 report, scientists from Newfoundland’s Memorial University say their models even suggest that eventually, these fish should start to get younger. Move over, Benjamin Button.

Biologists have in many cases been catching the same set of tagged lake trout since 1968. Each time, they’re weighed and measured, and males’ sperm quality is tested. Although lake trout can live upwards of 50 years and have reached 60-plus, this is rare due to pressures from fishing and predators. However, there are no predators big enough to eat adult trout in the research lakes, and fishing is prohibited, allowing many to reach ripe young ages.

Blood samples are also taken from fish to check their DNA. Specifically, the length of each fish’s telomeres is a key part of the study. Made of proteins, telomeres are caps at the ends of DNA segments that protect chromosomes from mutations as they divide, like shoelace tips for genetic strands.

The thing about these protective caps is that they get “worn down” each time a DNA sequence replicates when cells divide. Telomeres are longest when we’re young, and gradually shorten. When they get small enough, it triggers the breakdown of biological function — in other words, aging— in that cell. Finding a real-life example of telomeres staying intact over decades is a first. The harder task may be finding how it happens. The study authors hope that if the processes that let trout stay biologically young can be identified, it could broaden our understanding of human aging, perhaps opening up treatment options.

Such a breakthrough would be welcome indeed, because when our telomeres get critically short, it doesn’t just mean we get wrinkled skin and liver spots. It also increases the risk of getting, and dying from, serious ailments like infections, cardiovascular disease, Alzheimer’s disease, and liver disorders.

How fast our DNA’s shoelace-tips get pared down is actually more important than initial length. For example, mouse DNA starts out with unusually long telomeres, but they wear down fast, which is why mice have fleeting lives. Our individual genetic makeup has an influence on the rate of telomere loss, and thus, how fast we age. We all know families whose elders tend to stay healthy into their 90s, and others where they typically don’t age well. We’re stuck with this part.

However, we can pump the brakes on telomere loss in some ways, because environment and lifestyle play a huge role in how fast we age. Factors that speed up the rate of telomere attrition include chronic stress, air pollution, early-life trauma, alcohol consumption, and eating a lot of processed foods and sweets. Other things slow the loss of telomere length, such as exercise, good sleep habits, and eating a healthy diet.

It turns out that being kind has also been shown to protect our telomeres. As a bonus, practicing kindness is a proven way to reduce stress levels, which in turn helps keep telomeres from eroding. Now there’s a win-win strategy for the world.

The obvious follow-on is that we should do the stuff our moms (and doctors) told us to do: exercise, eat well, sleep well, don’t drink to much, and above all, be kind to others.