One lake in northeast China is home to large amounts of fish, nearly twice the size of any lake elsewhere. With an age-old ice fishing tradition now underway, many of these fish are getting reeled in. 

A full net of fish brings joy to Chagan Lake's fishermen. They have spent hours braving the cold, with temperatures reaching 20 degrees Celsius below zero.

Nowadays their centuries-old fishing techniques get a little help from modern machinery.

A fishing master told CGTN that they have kept the tradition of using horse-towed wheels and human labor to fish, because if they had started to industrialize it, it would not be environmentally friendly. 

The most popular fish inside Chagan Lake is the bighead carp weighing above five kilograms – at least twice the size of a regular carp. Big sized carp are only found in the lake if newly-hatched fish are replenished on time and the lake's eco-system is in check. During the warmer months people can easily spot lotuses, water chestnuts, and algae. That is one of the main reasons why fish can grow so big here in Chagan Lake. The fish can feed on plants, their seeds and insects.

The wintry retreat has also grown in popularity, attracting thousands of locals and visitors alike. That means more people now take on the responsibility of keeping the lake's health in check.

"There are a lot of tourists as well as small food vendors during the ice fishing season. Sometimes, they will leave trash behind. We have to make sure to clean up each day and leave no litter on the lake," said Shan Junguo, a spokesperson for Chagan Lake Fish Farm.

As fish signify long-lasting prosperity in Chinese culture, it is important for people to keep that in mind – to grow big fish and keep ice fishing a rich tradition, and to keep Chagan Lake clean.