The solitary fish named Mambo stopped eating and seemed to be missing its human visitors—so aquarists attached photos of human faces and uniforms to the side of its enclosure

How do you perk up a lonely fish? This may sound like the start of a particularly silly joke, but it was a very real challenge faced by staff at a Japanese aquarium when they noticed their sunfish was ailing.

Without its usual crowd of spectators, Kaikyokan’s sunfish essentially started to fall into a deep-sea depression.

An aquarium in Japan closed Dec. 1 for renovation work, much to the apparent dismay of a lone sunfish. It missed people and stopped eating.

A solitary sunfish at an aquarium in Japan lost its appetite, began banging into the side of the fishtank and appeared unwell days after the facility closed last month for renovations.