Archerfish (Toxotes chatareus) can be trained to recognise a human face, revealed a new study conducted by four researchers from the University of Queensland in Australia, reported CNN. The discovery is significant as fishes are not known to have a neocortex, which in humans is responsible for sensory perception, motor commands, spatial reasoning, conscious thought and language.

The study, published in the journal "Scientific Reports," suggests that the tropical species has amazing pattern discrimination abilities and can be trained to differentiate between two photographs of humans with great accuracy. The scientists chose archerfish because they can spit jets of water, and this helped researchers understand its responses.

During their research, the scientists presented photographs to their subjects and taught them to choose one over the others by giving them treats (fish feed) and repeating the process over a period of a few days to up to two weeks. Their subjects managed to get it right 81% of the time, even when they had to chose from a range of as many as 44 new photographs. They impressed the researched with a higher accuracy of 86% when the photos they were trained to recognise were played around with, for instance by changing colour tones and head shapes.

"Humans use lots of devices to recognise people, including social cues. Fish are not doing this. For them, they are just looking for patterns," said co-author Dr Cait Newport, who is also a research fellow at Oxford University. Others who were part of the study include Guy Wallis, Yarema Reshitnyk and Ulrike E Siebeck.

Siebeck was part of a similar experiment in 2015 that showed how the Ambon damselfish (Pomacentrus amboinensis) could recognise members of its own species with the help of facial patterns that are visible at ultraviolet wavelengths, according to National Geographic.

"The idea is that these patterns help the fish communicate secretly – without attracting the attention of predators, which, like us, are UV blind," Siebeck, who led the research, had said. The researchers believe that a fish's facial pattern may reveal more about its health and social standing. However, no experiment to that end has been conducted so far.

"I was amazed at how well these fish could discriminate facial patterns that were almost identical to my eyes," she had added after her experiment, which was presented at the Behaviour 2015 conference held in Cairns, Australia.