People work at a koi farm in Sanshilipu town in Gaotang county, Shandong province. [Photo provided to China Daily]

Years ago, the low-lying land along the old course of the Yellow River around Sanshilipu town in Gaotang county, Shandong province, held back the development of villages in the area, but it is now being used to raise koi fish, giving a boost to villagers' livelihoods.

In late October, the town enters its peak season for koi sales. At a koi park, several varieties of koi with striking white, black, gold and red hues swim gracefully in ponds, attracting potential customers. "Our fish have been selling like hotcakes recently," Xia Qingjun, the manager of a koi farming cooperative at the park, said while preparing more than 300 koi for shipment to cities outside Shandong.

Over the past few years, the town has tapped into its abundant water resources to develop the koi farming industry. That has led to the formation of an integrated koi industry that encompasses scientific research, breeding, farming, sales and tourism.

The town government has sought guidance from experts at research institutes, who provide regular technical assistance to koi farming enterprises and individual farmers.

Initially, earthen ponds were used to raise fish, which resulted in low survival rates. However, with the introduction of standardized ponds, each housing 50,000 koi of the same size, the survival rate has significantly improved, said Jia Qinghe, 51, who has been farming koi for 13 years. Farmers in the town are also introducing an aquaponic system to cultivate koi and vegetables from the same water source.

Water containing fish waste is pumped into the vegetable-growing area from a pond that is home to fish. The waste fertilizes the crops. The plants absorb the nutrients and clean the water, and the clean water flows back to the pond.

"This system not only achieves a symbiosis between fish and vegetables but creates an indoor landscape," said Ma Chuansheng, who is in charge of building the system.

Sanshilipu has dedicated over 67 hectares of land to koi farming, the town government said, with the capacity to breed over 100 million koi a year. To expand the market, local fish farmers have embraced e-commerce platforms and livestreaming to promote sales. "During the shipment, the fish are placed in specialized packaging bags filled with oxygen. They can endure a two-day journey without any problem," said one livestreaming host seen promoting koi at the park in late October.

The town's deputy Party secretary, Xu Qingpan, said around 100,000 packages of koi are dispatched every year, generating sales close to 100 million yuan ($13.8 million).

The koi industry in Sanshilipu has also promoted the development of nearby towns in the county, which the China Fisheries Association recognized in 2021 as the "koi capital" of China.

That recognition saw 100 breeders from across the country bring around 2,000 koi to participate in a competition in the county in October where the fish were judged on the basis of their patterns, colors and weight. "Previously, we were reliant on purchasing high-quality koi from abroad. Now, we have our own techniques to breed koi," said Guo Mengmeng, a 35-year-old koi breeder from the county.

A premium koi can cost thousands of yuan, and if a fish wins a competition, its price can be even higher, Guo said. The county has over 533 hectares of ponds dedicated to farming around 30 varieties of koi, which has become an engine to drive local economic development.