Lonely fish loves cardboard 'friends'

Sunfish are absolutely huge when fully grown, but start off tiny when they're born

How do you cheer your pals up if they're feeling a bit down?

You might tell them a funny joke, play some games with them, or just simply spend time with them.

But how about cheering up a fish?

Staff at an aquarium in Japan think they've found the answer, as they've stuck pictures of humans around a sunfish's tank to try and help it feel less lonely.

Shimonoseki Aquarium said on social media platform X that the fish is usually very curious with visitors, and so it seemed as though it missed them when they closed to the public

The people working at the aquarium in Shimonoseki noticed the sunfish looking a bit down in the dumps when they closed for refurbishments in December, and visitors were no longer coming in.

The huge flat fish weighed 28kg when it came to them, but it wasn't eating and was starting to lose weight.

It would refuse to eat the jellyfish it usually chowed down on, and started rubbing its belly against the tank.

Sunfish usually live alone in the ocean but the one in the Shimonoseki Aquarium in Japan had become accustomed to visitors

There were lots of theories put forward for why the fish was feeling out of sorts.

But then someone suggested the fish might be missing visitors, and the sounds they make... and it turned out they were right.

The aquarium team said that once the staff uniforms and pictures of cardboard people were taped to its tank, it immediately started eating more and seemed generally happier.

Sunfish usually live alone in the ocean but it seemed as though this one had become used to the crowds of people coming to visit it.

Mai Kato, a member of staff at the aquarium, said she hoped that more people would now take interest in the sunfish, and even wave to it in front of the tank.

Surprising sunfish facts

The ocean sunfish can measure 11 feet, almost twice as long as a human

• The scientific name for sunfish is mola mola

• Mola in Latin means 'millstone'

• They are the world's largest bony fish

• They can weight up to 2.5 tons (2500 kilos) - that's heavier than a rhino!

• Their rounded shape is due to a back fin they're born with which never grows

• They usually live on their own in the ocean

• Newly hatched sunfish can weigh just a gram, and grow huge amounts into adulthood - some can grow to be 60 million times larger than when they hatched