When summer arrives, sunbathing becomes a popular pastime. Not only do humans like to soak up the sunshine, but so do an interesting fish species.

Ocean sunfish, a giant fish that lives in tropical and temperate water, is a true sunseeker. It is one of the most peculiar and mysterious water dwellers in the world, with unconventional looks.

This fish does not have a true tail like others. The part of the tail looks like as if someone had cut its true tail off its body. As the largest bony fish in the world, the ocean sunfish has a size that could range from three to four meters from fin to fin.

It is not hard to imagine how surprised and possibly scared divers could be when they first encounter this underwater giant. But it has a gentle temper with strong curiosity. When in contact with humans, the fish is merely interested in knowing what the divers are doing, without hostile purposes.

The ocean sunfish is an avid sunbather. It can spend hours floating on its side on the water surface and enjoys soaking up the sunshine. This habit enables it to regulate its body temperature, after returning from the cold deep sea. Sunlight also helps kill parasites on its body surface, along with sea birds that clean the fish.

The ocean sunfish can lay over 300 million eggs at a time, but not all of them hatch. The sunfish larvae are only two millimeters in length and can grow 60 million times in size over the course of their life.

The fish is currently listed as "Vulnerable" on the IUCN Red List, threatened by bycatch risks and habitat pollution. Its diet includes jellyfish, but it's very likely to swallow floating plastic bags.

(Cover image designed by CGTN's Qu Bo via VCG)

(If you want to contribute and have specific expertise, please contact us at nature@cgtn.com.)