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.

Staff had noticed that the sunfish was showing signs of distress after the aquarium was closed for refurbishment

Fish have feelings too – at least if a lonesome sunfish in a Japanese aquarium is anything to go by. Animal caretakers at the Kaikyokan in the southern city of Shimonoseki were concerned when Mambo the sunfish appeared to fall ill, shortly after the facility closed for renovations in early December.

SHIMONOSEKI: A lonely ocean sunfish in a Japanese aquarium, which seemed to be missing its human visitors and caretakers during the facility’s closure, has found a surprising source of comfort.

A video obtained by Reuters on Tuesday (January 21) showed how an aquarium in Japan's Yamaguchi has come up with a unique solution to improve the deteriorated health of its beloved sunfish affected by the lack of visitors - making cutouts of human faces to paste them on the tanks.

Staff members believe the sunfish stopped eating when the aquarium was temporarily closed because it was lonely.

The aquarium noted, “We didn't know the cause [of the fish feeling unwell] ... but one of the staff members said, ‘Maybe he's lonely without the visitors?’ "