Skip to main content

From blue to green, red or orange: Fish put on new light

By Steve Almasy, CNN
updated 12:43 PM EST, Thu January 9, 2014
A green biofluorescent chain catshark (Scyliorhinus retifer) A green biofluorescent chain catshark (Scyliorhinus retifer)
HIDE CAPTION
Glowing fish
Glowing fish
Glowing fish
Glowing fish
Glowing fish
<<
<
1
2
3
4
5
>
>>
STORY HIGHLIGHTS
  • When hit with special blue light, 180 species of fish light up
  • Researchers think it may play a role in mating or in communication
  • Scientists discovered a glowing green eel when looking at reefs for biofluorescence
  • Some fish have yellow filters in their eyes, which can help them see the light show

(CNN) -- There is a light show in the ocean that you can't see, but many fish can. There's quite a display of neon greens, reds, and oranges going on underneath the surface.

Still, the discovery of what is hidden from human eyes -- biofluorescence in 180 species of fish -- brings up many questions for researchers.

Do fish use it to communicate with others? Do they use it to mate? What is its function?

Biofluorescence occurs when an organism absorbs blue light, transforms it and emits it as another color.

A team of researchers from the American Museum of Natural History and other scientific organizations published a study Wednesday in the online journal PLOS ONE, reporting the findings of the first in-depth look at biofluorescence in fish.

"We've long known about biofluorescence underwater in organisms like corals, jellyfish, and even in land animals like butterflies and parrots," said the study's co-author, John Sparks, who is a curator in the Museum's Department of Ichthyology.

He said the team stumbled on an eel that glowed green while he and a partner were studying a reef in the Cayman Islands. The discovery in a photograph of the eel lighting up underneath the blue lights they used led them to make four more trips in different parts of the world to get a closer look at the glow show.

The expeditions to the Bahamas in the Caribbean and Solomon Islands in the Pacific revealed a variety of fish living around coral reefs -- including sharks, rays, eels and lizerdfishes -- that exhibited bioflourescence. s

"Many shallow reef inhabitants and fish have the capabilities to detect fluorescent light and may be using biofluorescence in similar fashions to how animals use bioluminescence, such as to find mates and to camouflage," Sparks suggested, while adding the reasons will need further study.

So how do the fish recognize it? Many of them have yellow filters in their eyes, "possibly allowing them to see the otherwise hidden fluorescent displays taking place in the water," a news release from the museum of natural history said.

"The cryptically patterned gobies, flatfishes, eels, and scorpionfishes -- these are animals that you'd never normally see during a dive," Sparks said. "To our eyes, they blend right into their environment. But to a fish that has a yellow intraocular filter, they must stick out like a sore thumb."

Some scientists cautioned that the bioflouresence might look neat in photos using special lights but also have no function.

Nico Michiels, a zoologist at the University of Tübingen in Germany, and Steven Haddock of the Monterey Bay Aquarium Research Institute in California, indicated to Science Now that the need for special technology to view what the website called weak fluorescence "casts doubt on the usefulness of the coloration in the fish's dimly lit natural environments."

Sparks said it will be interesting to see what the team finds next.

"This paper is the first to look at the wide distribution of biofluorescence across fishes, and it opens up a number of new research areas," he said.

He added that there may be fluorescent proteins involved, ones that could be used in biomedical research.

ADVERTISEMENT
Part of complete coverage on
Science news
updated 3:34 PM EDT, Mon August 25, 2014
Nichelle Nichols has spent her whole life going where no one has gone before, and at 81 she's still as sassy and straight-talking as you'd expect from an interstellar explorer.
updated 7:52 AM EDT, Tue July 22, 2014
The world's largest flying aquatic insect, with huge, nightmarish pincers, has been discovered in China's Sichuan province.
updated 8:10 AM EDT, Mon June 23, 2014
As fans of "Grey's Anatomy," "ER" and any other hospital-based show can tell you, emergency-room doctors are fighting against time.
updated 7:59 AM EDT, Thu May 29, 2014
Ask 100 robotics scientists why they're inspired to create modern-day automatons and you may get 100 different answers.
updated 12:35 PM EDT, Fri June 13, 2014
From the air, the Namibian desert looks like it has a bad case of chicken pox.
updated 12:43 PM EDT, Wed May 28, 2014
The trend for nature-inspired designs has spread across industries from crab-style deep-sea vessels to insect-inspired buildings.
updated 8:22 AM EDT, Sun May 25, 2014
Consider it the taxonomist's equivalent of a People magazine's Most Beautiful List.
updated 11:32 AM EDT, Fri May 9, 2014
For the first time, scientists have shown it is possible to alter the biological alphabet and still have a living organism that passes on the genetic information.
updated 7:48 AM EDT, Mon May 5, 2014
Do we really want to go the route of "Jurassic Park"?
updated 8:44 AM EDT, Fri May 2, 2014
Catch a train from the sky! Perhaps in the future, the high-rise superstructures could help revolutionize the way we travel.
updated 10:58 AM EDT, Mon May 5, 2014
In a nondescript hotel ballroom last month at the South by Southwest Interactive festival, Andras Forgacs offered a rare glimpse at the sci-fi future of food.
updated 10:12 AM EDT, Thu March 20, 2014
For a Tyrannosaurus rex looking for a snack, nothing might have tasted quite like the "chicken from hell."
updated 6:29 PM EDT, Fri March 14, 2014
Everyone is familiar with Tyrannosaurus rex, but humanity is only now meeting its much smaller Arctic cousin.
updated 12:12 PM EST, Thu March 6, 2014
At about 33 feet long, weighing 4 to 5 tons and baring large blade-shaped teeth, the dinosaur Torvosaurus gurneyi was a formidable creature.
updated 6:43 AM EST, Fri February 21, 2014
This Pachyrhinosaurus can go to the head of its class.
updated 8:04 AM EDT, Thu March 27, 2014
Science is still trying to work out how exactly we reason through moral problems, and how we judge others on the morality of their actions. But patterns are emerging.
updated 7:06 PM EST, Thu February 27, 2014
A promising way to stop a deadly disease, or an uncomfortable step toward what one leading ethicist called eugenics?
updated 8:07 PM EST, Fri February 14, 2014
Seattle paleontologists safely removed the largest fossilized mammoth tusk discovered in the region from a construction site.
updated 6:13 AM EDT, Tue April 23, 2013
A mysterious, circular structure, with a diameter greater than the length of a Boeing 747 jet, has been discovered submerged about 30 feet underneath the Sea of Galilee in Israel.
updated 5:25 PM EST, Fri January 17, 2014
Every corner of the planet offers some sort of natural peculiarity with an explanation that makes us wish we'd studied harder in junior high Earth science class.
updated 8:20 AM EST, Thu November 14, 2013
Deep in a remote, hot, dry patch of northwestern Australia lies one of the earliest detectable signs of life on the planet, tracing back nearly 3.5 billion years, scientists say.
updated 3:10 PM EDT, Wed September 4, 2013
We leave genetic traces of ourselves wherever we go -- in a strand of hair left on the subway or in saliva on the side of a glass at a cafe.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT