A longtooth grouper in a Nagoya aquarium has become so accustomed to humans that it now demands to be petted and have its teeth brushed by its keeper.
Named Futami No. 1, the meter-long fish at Port of Nagoya Public Aquarium swims up to its 35-year-old keeper, Hitoshi Okamoto, when he visits its tank.
"I've never seen a fish that has got used to humans this much," Okamoto said.
Physical contact between the two began about a month after the fish was moved from an aquarium in Ise, Mie Prefecture, in 2014.
At first, the fish refused to eat. Okamoto tried poking its gums when it opened its mouth, which the fish appeared to enjoy, he said. The rare contact escalated to toothbrushing this year.
As the fish has sharp teeth, only Okamoto is allowed to touch it.
"The fish may have learned that it feels nice to be touched by human hands, just like it is touched by the fins of the bluestreak cleaner wrasse," a small fish that cleanse longtooth groupers of parasites, said Tetsuo Kuwamura, a professor at Chukyo University who specializes in understanding fish behavior.
