First impressions matter: wild fish can actually recognize humans in the ocean.

The ocean covers a significant portion of the Earth's surface and is home to an astonishing number of marine inhabitants. Many of these creatures continue to surprise scientists, and now it’s the turn of wild fish — researchers have found that they can apparently distinguish between humans beneath the water's surface — at least when the humans are wearing differently colored clothing, reports The Guardian.

The study was conducted by a team from the Max Planck Institute for Animal Behavior in Germany and suggests that their findings could indeed change our relationship with wild fish. During the research, scientists trained a bream to follow a specific diver for treats.

It is known that some domestic animals, or those living close to humans, can tell one person from another. This ability, according to scientists, may be related to the fact that certain people are more likely to share resources or pose a threat. However, such behavior is less commonly observed in wild animals.

According to the lead author of the study, Maelan Thomasek, in their new analysis, he and his colleagues discovered that wild fish can differentiate between humans, likely based on the clothing they wear. The authors argue that fish utilize simple mechanisms they employ in their daily lives and adapt them to recognize people.

In the first phase of the study, the researcher spent 12 days training a wild sea bream and black sea bream to follow him, repeatedly offering food to the fish and rewarding those who followed. Next, another researcher joined the trainer, dressed either in the same diving gear or in gear with colorful spots and fins. In both scenarios, the two divers swam in different directions before returning to the starting point and repeating the process.

Although both researchers carried food, the fish received rewards only if they followed the trainer. In total, the team conducted 30 trials for each species and used video surveillance to count the number of fish following the diver. The results indicate that when the divers were dressed in different outfits, both species of fish followed the trainer more often than the other researcher, and this preference became increasingly pronounced as the trials continued.

The study's authors also found that certain individual fish were better at recognizing the diver and following him — suggesting that the fish can indeed identify people. Interestingly, when the divers were dressed identically, this effect was not observed.

The team states that since the fish had no prior experience interacting with humans, it is likely that they used existing capabilities based on visual cues to distinguish between the divers.

The authors of the study believe that their findings could prompt us to reconsider how we interact with fish around the world, including their capture.