Researchers have established that reef fish see colors that humans cannot.

Researchers at The University of Queensland have established that reef fish see colours that humans cannot.

A team from Professor Justin Marshall's Sensory Neurobiology Lab at the Queensland Brain Institute ran a series of behavioral experiments with trigger fish, in a bid to decode how they see the world.

Professor Marshall said previous studies had looked into how goldfish saw colour, but this was the first study into how reef fish discriminate colours.

"Coral reefs are the most colourful environments in the world, and it's now become clear that reef fish see colours we can't," Professor Marshall said.

"Some reef fish, such as the anemonefish 'Nemo' and other damselfish can see the UV wavelengths we protect ourselves from.

"Triggerfish, on the other hand, see more or less the same colour range we do but their colour discriminations are different.

"Thinking about it, this is no big surprise. Their colour tasks are blue-biased, as they live in a blue ocean.

"Ironically, as the colours of the reef change and disappear because of climate change, we are just beginning to understand how reef inhabitants see and experience their vibrant world," he said.

Professor Marshall said Dr Connor Champ led a series of detailed behavioural tests, where trigger fish were rewarded for discriminating against progressively similar colours.

It emerged that trigger fish see colours in some colour regions in more detail than humans.

"Many people ask me 'Why study fish?' and my first answer is: "Because I love them," Professor Marshall said.

"But this sort of comparative look at animal systems is vitally important to understand not just the beauty of nature and how to look after it, but to consider the possible applications in the human world."

Comparative colour vision research at QBI is helping in cancer detection, satellite design and data storage on computers.

Coral reef fish come in a stunning array of colors, which double for them as means of camouflage and visual communication. Though we often admire the beauty of these fish, a new studypublished in Royal Society Open Science finds that humans can’t even begin to appreciate their color variation to the extent that the fish themselves can.

Researchers at The University of Queensland, Australia, set up an experiment in which trigger fish — a group of brilliantly-colored coral reef species — were shown progressively similar colors in the blue region of the spectrum. When they successfully discriminated the colors from one another, they received a reward.

It became apparent that these fish were able to distinguish colors with vastly greater resolution than humans — they could see clear colors in what, to the human eye, appear as nothing more than blurred boundaries between pairs of neighboring colors.

"Coral reefs are the most colourful environments in the world, and it's now become clear that reef fish see colours we can't," says study senior author Justin Marshall in a press release.

He explains that, while some reef fish, such as the clownfish (i.e. Nemo), can actually see wavelengths that are beyond the spectrum of human perception, like ultraviolet waves, trigger fish “see more or less the same colour range we do but their colour discriminations are different.”