Biofluorescence, the process of absorbing high-energy light and re-emitting it as low-energy wavelengths, has been observed in various vertebrate and invertebrate lineages, particularly among fish. Research conducted by the American Museum of Natural History indicates that fish biofluorescence can be traced back at least 112 million years and has evolved over 100 times, predominantly in fish inhabiting coral reefs.
Phylogenesis of teleosts showing ancestral state reconstruction (absence/present) of biological fluorescence. Image credit: Carr et al., doi: 10.1038/s41467-025-59843-7.
“Researchers have long known that biological fluorescence is prevalent in marine creatures, including sea turtles and corals, particularly among fish,” stated PhD Emily Kerr, a student at the American Museum of Natural History.
“To truly grasp the reasons and methods behind this unique adaptation, we need to explore the evolutionary background and the variety of biofluorescence currently utilized for camouflage, predation, or reproduction.”
In a first study published in the journal Natural Communication, Carr and colleagues investigated all known biological fluorescent extents, focusing on a species of bony fish, which comprises the largest living vertebrate group today.
This research identified 459 biological fluorescent species, including 48 previously unrecognized as biologically fluorescent.
The researchers discovered that biological fluorescence has evolved over 100 times in marine teleost fish, dating back to approximately 112 million years ago, with the initial occurrence found in eels.
Furthermore, fish species residing in or near coral reefs developed biological fluorescence approximately ten times faster than their non-reef counterparts, leading to a surge in fluorescent species following the mass extinction event around 66 million years ago that wiped out non-avian dinosaurs.
“This pattern coincides with the emergence of modern coral reefs and the rapid infiltration of fish into these environments, particularly after a significant loss of coral diversity due to the Cretaceous extinction,” Kerr explained.
“These relationships imply that the rise of contemporary coral reefs may have spurred the diversification of fluorescence in reef-associated teleost fish.”
Among the 459 documented biological fluorescent extents indicated in this study, the majority are linked to coral reefs.
In a second survey published in the journal PLOS 1, Kerr and co-authors employed a specialized photographic system with ultraviolet and blue excitation lights, alongside emission filters, to analyze the wavelengths emitted by fish from the ichthyology collection at the American Museum of Natural History.
These specimens, collected over the past 15 years during museum expeditions to locations like the Solomon Islands, Greenland, and Thailand, had shown fluorescence previously; however, the full spectrum of biological fluorescence emissions remained unexplored.
This study unveiled a broader diversity in the colors emitted by teleost fish, with some displaying at least six distinct fluorescence emission peaks across various wavelengths, surpassing prior reports.
“The unexpected variation observed among a wide array of these fluorescent fish suggests that they may utilize highly diverse and intricate signaling systems based on species-specific fluorescent emission patterns.”
“As these studies illustrate, biological fluorescence is extensive and remarkably phenotypically diverse among marine fish.”
“Our goal is to enhance our understanding of how fluorescence operates within these varied marine ecosystems and its role in evolutionary diversification.”
“The multitude of fluorescence emission wavelengths identified in this study could significantly impact the discovery of new fluorescent molecules that are routinely employed in biomedical applications, including the diagnosis and treatment of fluorescence-related ailments.”
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Carr et al. 2025. The extensive evolution of repeated biological fluorescence in marine fish. Nat Commun 16, 4826; doi:10.1038/s41467-025-59843-7
Carr et al. 2025. Marine fish display exceptional variability in biological fluorescence emission spectra. PLOS 1 20 (6): E0316789; doi: 10.1371/journal.pone.0316789
Source: www.sci.news
