Reef Fish Could See More Colors Than Humans

A new study reveals that reef fish could see wavelengths and some colors that cannot be seen by the human eyes.

The study, published in the journal Royal Society Open Science, suggests that some coral fish could see more or less the same color range as humans, but have different color discriminations. This suggests that reef fish could see certain colors in more detail than humans do.

"Some reef fish, such as the anemonefish 'Nemo' and other damselfish can see the UV wavelengths we protect ourselves from," said Justin Marshall, head of the Sensory Neurobiology Lab at Queensland Brain Institute, in a press release. "Triggerfish, on the other hand, see more or less the same color range we do but their color discriminations are different."

For the study, the researchers conducted a series of behavioral tests on lagoon triggerfish (Rhinecanthus aculeatus), a predatory marine animal commonly found in coral reefs across the Indo-Pacific. The researchers trained the triggerfish to respond to specific reward colors. The triggerfish was given a reward, in a form of food paste whenever they correctly discriminate progressively similar colors.

The researchers noted that the triggerfish could discriminate color better than humans and that they could see colors in more detail. The discovery, as described by Marshall, is no big surprise because considering that they are marine animals, the fish' color task is blue-biased.

However, even though it is just now that  science has began noticing and understanding fish' eyes for complex colors, the animals' environment continues to change color and disappear due to climate change and human activities. The researchers believe that such comparative look on how different animals see differently in nature could be used and applied in the human world. The comparative color vision research at Queensland Brain Institute could help in cancer detection, satellite design and data storage in computers.

The triggerfish used in the study were caught around Lizard Island, located in northern Queensland, Australia with the permission from the Great Barrier Reef Marine Park Authority and the Queensland Fisheries Service.