Fish Biofluorescence Dates Back 112 Million Years
The trait has evolved independently in animals more than 100 times.
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Two new studies led by Museum researchers shapes our knowledge about the origins and scope of fish biofluorescence—the flashy phenomenon in which light is absorbed, transformed, and emitted as a different color.
The work, published recently in Nature Communications and PLOS One, finds that fish biofluorescence is ancient, first occurring at least 112 million years ago, and has evolved independently more than 100 times since, particularly among fish that live on coral reefs. The two studies also reveal that fish biofluorescence involves a larger assortment of colors than previously reported.
“Researchers have known for a while that biofluorescence is quite widespread in marine animals, from sea turtles to corals, and especially among fishes,” said Emily Carr, a Ph.D. student in the Museum’s Richard Gilder Graduate School and the lead author on the two new studies. “But to really get to the root of why and how these species use this unique adaptation—whether for camouflage, predation, or reproduction—we need to understand the underlying evolutionary story as well as the scope of biofluorescence as it currently exists.”
Carr and collaborators, including her Ph.D. advisor, Museum Curator John Sparks, surveyed all known biofluorescent teleosts—a type of bony fish that make up the largest group of vertebrates living today. They ended up with a list of 459 species, including 48 species that were previously unknown to be biofluorescent.
Their work suggests that this unique phenomenon first arose in eels at least 112 million years ago and has evolved more than 100 times. The evolution rate is especially high in fish species that live on coral reefs—10 times the rate of non-reef species. The increase coincides with the recovery of coral reefs following the Cretaceous-Paleogene (K-Pg) extinction about 66 million years ago.
“These correlations suggest that the emergence of modern coral reefs could have facilitated the diversification of fluorescence in reef-associated teleost fishes,” Carr said.
The researchers used a specialized photography setup with ultraviolet and blue excitation lights and emission filters to look at the wavelengths of light emitted by fishes collected over the last decade and a half on Museum expeditions to the Solomon Islands, Greenland, and Thailand. Although the specimens in the study were previously observed fluorescing, the full range of their biofluorescent emissions was unknown.
The new work reveals far more diversity in colors emitted than had previously been reported. Some teleost families exhibit at least six distinct fluorescent emission peaks, which correspond with wavelengths across multiple colors.
“The remarkable variation we observed across a wide array of these fluorescent fishes could mean that these animals use incredibly diverse and elaborate signaling systems based on species-specific fluorescent emission patterns,” Sparks said.
References:
Carr EM, Martin RP, Thurman MA, et al. Repeated and widespread evolution of biofluorescence in marine fishes. Nat Commun. 2025. doi:10.1038/s41467-025-59843-7
Carr EM, Thurman MA, Martin RP, et al. Marine fishes exhibit exceptional variation in biofluorescent emission spectra. PLOS One. 2025. doi:10.1371/journal.pone.0316789
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