The district is maintaining 275 hectares of water surface for aquaculture, including more than 4,000 fish cages on the reservoir, with 25 cooperatives engaging in aquaculture and seafood processing. Annual aquatic output reaches over 1,800 tonnes, including about 1,200 tonnes of farmed fish. Since the beginning of this year, the farmed and caught fish output has hit over 500 tonnes. Aquatic species raised on the lake are quite diverse, including black carp, carp, red tilapia, naked catfish and catfish.

As one of the aquaculture cooperatives established early, after more than 10 years of operation, the Ho Quynh Aquaculture Cooperative in Chieng On commune provides Quynh Nhai’s Da River fish products to customers in northern provinces and cities. The cooperative currently has nine members, with more than 400 fish cages. Previously, it raised many different types of fish to diversify products. After grasping market demand, the cooperative shifted to farming high-quality snaked catfish under safe processes. Each batch takes at least 18 months, with an output of over 300 tonnes, mainly sold in major stores and supermarkets in Hanoi and some other provinces, earning each member 200-700 million VND (7,870-27,550 USD).

With the desire to diversify fish products farmed on the reservoir, a number of cooperatives and households have started pre-processing and processing of aquatic products. Along with selling fresh fish, last year, the An Binh Seafood Cooperative in Chieng Bang commune invested in a frozen warehouse to make frozen fish and shrimp, fish fillets and dried anchovy. In late 2023, with the support of the district authorities, its frozen Da River fish was recognised as a 3-star One Commune Once Product (OCOP) product, helping the cooperative improve production and business efficiency.

Also wishing to bring Quynh Nhai aquatic products to many consumers, Dao Thi Hieu in Muong Giang commune has created many products from Da River fish and shrimp such as fish cake, fish sausage, fish floss, fish rolls, and dried fish. In 2022, her family's Da River fish cake was recognised as a 3-star OCOP product. In addition, a number of cooperatives and business households in Quynh Nhai district are also developing products processed from seafood, such as fried shrimp, fish cakes with piper lolot, boneless fish, dried ditch fish and shrimp sauce, meeting the needs of customers.

Quynh Nhai district plans to encourage local households, businesses, and cooperatives to develop cage fish farming, combined with making processed aquatic products. The district will create conditions for units to participate in trade promotion activities at booths and fairs inside and outside the province to introduce typical local aquatic products.

Developing typical products of the reservoir area into OCOP items has been helping fish farmers create prestige for Quynh Nhai’s Da River fish products. In addition, cooperatives and households engaging in cage culture have always actively renewed production and business methods, grasped market demand to improve the fish quality, and diversified processed aquatic products, helping with the sustainable development of cage culture, thus bringing stable income to farmers.