Japanese aquarium comforts lonely sunfish with cardboard cutouts of fake visitors

When a beloved sunfish at the Kaikyokan Aquarium in Shimonoseki, Japan, stopped eating and seemed unwell, staff were baffled. The timing was peculiar: the fish’s decline began shortly after the aquarium temporarily closed for renovations in December 2024. Staff took various measures to address the issue, but nothing seemed to work—until someone floated an unconventional idea.

“Maybe it’s lonely because it misses the visitors?” a staff member suggested, according to a post from the aquarium on X. Initially, this theory seemed implausible. But, in a moment of hope, the team decided to dress up hangers with aquarium uniforms and add cardboard cutout faces to create makeshift "people." These figures were placed around the tank to simulate the presence of visitors.

“Then…the next day, it was in good health again!” the aquarium’s post announced triumphantly.

A photo shared by the aquarium shows the sunfish floating serenely in its tank, one eye turned toward the cutouts. Staff members have even been waving at the fish, further attempting to simulate the interactions it might have had with human visitors.

Though it might sound far-fetched, the aquarium’s explanation doesn’t seem entirely off base. Reddit user u/eternalityLP remarked, "People often talk about enrichment with all the cute animals but things like fish are often forgotten," highlighting the importance of mental stimulation for creatures like the sunfish.

Representative image by Canva.

This particular sunfish, they noted, is especially curious and has a habit of swimming to the front of its tank to greet guests. Without visitors, the fish stopped eating its usual jellyfish meals and even began rubbing against the sides of the tank. This sentiment resonated with u/imanoctothorpe, who shared, "Noooo this actually made me tear up :( my husband and I went to Kaiyukan a year ago and to think one of those was Kai san... damn."

This behavior led staff to worry about possible digestive issues or parasitic infections, as reported by Japanese newspaper Mainichi Shimbun.

Ocean sunfish, known for their distinctive bullet-shaped bodies and massive size, are fascinating creatures. Redditor u/r31ya humorously described them as "BEEG and Chill fish," capturing the internet’s affectionate fascination with these gentle giants. While they can weigh over 3,300 pounds and measure nearly 11 feet long in the wild, this aquarium specimen is significantly smaller. Sunfish typically inhabit the open ocean in temperate and tropical regions, but their appearances along shores from Australia to California often draw attention due to their unusual size and shape.

Creative depiction of an ocean sunfish by Canva.

This isn’t the first time a Japanese aquarium has found a creative way to address the social needs of its animals. Reddit user u/stumpyspaceprincess shared a story about a Maori wrasse during a dive, noting, "He really was so friendly and fascinating, at least one German diver got a lecture after letting him lead her off 😆." During the Covid-19 lockdown in 2020, Tokyo’s Sumida Aquarium asked the public to FaceTime its shy spotted garden eels. Without human interaction, the eels had become withdrawn, making it difficult for staff to monitor their health. By asking volunteers to video call the eels, the aquarium was able to help the animals reacclimatize to human presence.

After their sunfish’s remarkable response, the Kaikyokan Aquarium’s innovative approach should definitely be celebrated. And hopefully this trend will catch on around any other lonely fish out there.