That’s no illusion! It’s a glowing fish!
And I’m Sandra Tsing Loh with the Loh Down on Science.
Why do they glow like that anyway? Is it magic? No…
Emily Carr and team at the American Museum of Natural History wanted answers.
Using special lights, they spotted biofluorescence, where fish absorb blue light and re-emit it as green or red. They surveyed hundreds of species and mapped glowing traits onto the fish family tree.
And? Biofluorescence evolved independently over a hundred times, across different ecosystems, dating back over a hundred million years! Reef fishes developed their glow the fastest.
Why glow? Scientists think it helps fish hide, talk to each other, or even find love.
Now, for my next trick… Fluorescence!
Reference: Carr, E. M., Martin, R. P., Thurman, M. A., Cohen, K. E., Huie, J. M., Gruber, D. F., & Sparks, J. S. (2025). Repeated and widespread evolution of biofluorescence in marine fishes. Nature Communications, 16, 4826. https://doi.org/10.1038/s41467-025-59843-7