Fish Can Recognize People From What They're Wearing

While they're probably not judging anybody on their fashion choices, fish can tell people apart based on their outfits, according to a new study. Researchers say sea bream in the Mediterranean Sea could tell divers apart from subtle differences in their diving gear and followed the one that would reward them with food, the Smithsonian reports. "When divers wore identical dive gear, correct identification of divers was greatly diminished, suggesting that discrimination was based predominantly on visual cues," researchers wrote in a study published in the journal Biology Letters.

Researcher Katinka Soller from the Max Planck Institute of Animal Behavior initially fed the fish, who have excellent color vision, wearing a bright red outfit. She says the fish still followed her instead of fellow researcher Maelan Tomasek when she switched to plainer diver gear, with Tomasek wearing slightly different gear, including fins of a different color. She believes that over time, the fish would have been able to tell them apart from their hair and hands. "We already observed them approaching our faces and scrutinizing our bodies," Soller says. "It was like they were studying us, not the other way around."

Soller learned to recognize some of her followers, including "Bernie with two shiny silver scales on the back and Alfie who had a nip out of the tail fin." Researchers say they launched the study after the sea bream thwarted an attempt to study much more basic fish cognition by continually singling out the diver who was carrying food for rewards, even after decoy divers were sent in, the Times of London reports. "What is most surprising here is that we are surprised," Tomasek says. "It really shows that we have strong misconceptions of fish cognition. We always think that they're dumb." He adds: "This attitude of humans towards fish is wrong. The fish are super curious. It's they who came, willingly, to engage with us." (More fish stories.)