Jul 14, 2025
I’ve been thinking about mermaids recently—for no particular reason—and I was thinking, as one does, about the biology and evolutionary pressures that would cause mermaids to evolve. And I was watching something on ray-finned fish a couple weeks ago and thought, “hmmm, what if mermaids were ray-finned fish?” Which led me down the rabbit hole of a type of fish native to the Nile, bichirs (Polypterus), they are what one might call a “living fossil”. They have “primitive” lungs, and they can “walk” with their strong pectoral fins. So I thought maybe this air breathing, land crawling fish could be a good candidate for what mermaids could evolve from. Anyway, here’s a bichir mermaid.