Moreover, this newly discovered age exceeds the life expectancy of any known freshwater fish by nearly 40 years. (The oldest known saltwater fish - and vertebrate - is the Greenland shark (Somniosus microcephalus), which can live for centuries.)

Sadly, the same techniques that revealed the tremendous longevity of these fish have also revealed their desperate straits. But what we've learned from the death of Grandma Fish could help save the species.

Biologists had suspected that bigmouth buffalo might live for longer than we knew, so they set out to discover just how old these animals can get.

Between 2011 and 2018, they caught a large number of fish for data collection. Some of the specimens were photographed, measured, sexed, and tagged before being released back in the wild, so the team could measure changes over time.