Biofluorescence—the ability of living organisms to absorb high-energy light and reemit it in vivid colors—has recently been shown to have an astonishingly deep-rooted history in reef fish. Scientists from the American Museum of Natural History discovered that this glowing trait first emerged around 112 million years ago, concurrently evolving independently over 100 times, mostly in fish species associated with coral reefs. This evolutionary pattern suggests a strong link between reef habitats and the emergence of biofluorescence as a survival tool, not merely a spectacular visual quirk.
The study mapped 459 biofluorescent teleost fish, including 48 species previously unknown to display this trait. Reef-associated species were found to evolve biofluorescence at ten times the rate of non-reef species, a trend that surged after the Cretaceous-Paleogene extinction about 66 million years ago . Experts believe that the vibrant, heterogeneous light environment within coral reefs fostered selective pressures for this trait, enabling enhanced communication, camouflage, or mating signals under low-light conditions .
Understanding this ancient glow has profound implications. Not only does it provide insight into fish diversification and adaptation, but it also underlines the importance of conserving reef ecosystems—because many biofluorescent species rely on the very reef structures at risk from bleaching and habitat loss. By protecting coral reefs, science can continue to uncover the evolutionary stories written in fluorescent light, enriching our knowledge of nature’s complexity and resilience.
