Tourists watch a mermaid performance in Xiamen, Fujian province.[Photo by Shen Weibin/chinadaily.com.cn]

As the activity became popular in the coastal city, she quit her job and became a mermaid instructor.

"Mermaid diving is an emerging sport that requires both swimming and yoga skills," she said.

Now she teaches about 10 trainees every month. During the recent summer vacation, she even had some students who came to learn from her.

She said some of the trainees want to be professional mermaid divers. A performer must be able to hold her breath underwater for one minute and complete various movements.

You said she spent a lot of money on underwater photography equipment, which she uses to promote interest in the sport and take pictures of her trainees in action.