Glories of a hidden world

For Zhang, who has ankylosing spondylitis, a form of spinal arthritis, underwater photography that requires him to work in cold water is not an ideal career. But dreams sometimes require sacrifice.

"In the first few years as an underwater photographer, I had to borrow money from my parents to make ends meet," he says. After his images established his reputation, companies contacted him offering work.

He also gives lectures on ocean biology and sometimes arranges diving tours for people.

Located in the nutrient-rich Coral Triangle, Anilao in the Philippines, home to an astounding amount of marine wildlife, has been one of his most frequently-visited destinations. November is the best time for underwater photography in Anilao, according to Zhang.

Late last year, he recorded an eel larva during a nighttime dive off the coast there. "Leptocephalus is not easy to capture, because it moves super fast and randomly," he says.

During another dive in Anilao, Zhang encountered a blanket octopus, unfolding and displaying a colorful web.