He holds a brittle star. [Photo provided to China Daily]

His reputation rose as the number of his followers grew online.

Zhang's overnight sensation also stirred up doubts about him.

Some suggested Zhang's success was due to a whole team's support.

"I operate the official Weibo account myself. And, I answer all the questions alone," says Zhang.

"I tried to find others to share some of the burden but I am still alone at the current stage. I hope some successors will show up one day."

Zhang is considering releasing several video programs or doing a live broadcast to better introduce his knowledge to others.

"Videos can help promote knowledge in a more direct way," Zhang says.

"For instance, as spring comes, many people cannot distinguish the differences between peach flowers and cherry blossoms. Through videos, I can teach people how to spot the difference."

During his work, Zhang needs to identify different species from not only photos but also drawings.

He has gradually developed his own drawing skills, inspiring him to publish his first book last year.