Technical tips for successful breeding of squarehead carp

AgriSearch: Click here to listen to the audio

Squarehead carp is currently being widely farmed due to its many outstanding advantages compared to ordinary carp. Selected from large, mature individuals, if properly farmed, it can reach a weight of 8 taels. That is why farming squarehead carp is currently the choice of many farmers.

Table of Contents

Advantages of Squarehead Carp

Farmers have recognized many advantages of this fish, including fast growth rates, large size, resistance to diseases, good resistance to weather conditions, and tasty, nutritious meat. Squarehead carp can tolerate both hot and cold temperatures.

Farmers who raise squarehead carp share that this type of fish consumes less feed, specifically only 1.4 kg of feed is needed to produce 1 kg of fish, while ordinary carp requires 2 kg. This is why farming squarehead carp helps farmers save on feed costs.

Squarehead carp grow very quickly. On average, farmers can achieve 6 fish per kilogram in 4 months. When farmed for 7 months, the size of the fish can reach 500 – 800g. In some cases, squarehead carp can reach a weight of up to 900g if farmed properly. If you want to learn how to farm squarehead carp for fast growth, continue reading below!

Characteristics of Squarehead Carp

In terms of appearance, squarehead carp is similar to ordinary carp, but when it grows larger, its head becomes larger and square-shaped, its body is slightly curved, its belly is saggy, it has a long tail, thick fins, and dark yellow scales with two black spots on its tail.

Squarehead carp reproduces during the rainy season, with a strong parental behavior and a high reproduction rate in June and July.

Techniques for Farming Squarehead Carp for Fast Growth

Selecting Breeds

This is an important step when farming any fish, and for squarehead carp, you need to select individuals that meet the following criteria:

• Weighing 300-350 individuals per kilogram
• The breeds should be uniform, swim fast, and have no deformities
• No signs of injuries, shiny and bright scales

Preparing Ponds for Farming

The minimum area for squarehead carp ponds is 200m2, and they must be close to a clean water source with the ability to control the water source, and the soil must not be contaminated with salt. The pond should have a water depth of 1.6-2m and a 15-20cm sediment layer on the bottom. The farming pond must have a separate water supply and drainage system, and an external protective net.

Arranging cages in the farming pond to facilitate monitoring and management.

Before adding water and releasing the fish, the farming pond should be renovated by drying out the water and then eliminating all impurities and cleaning the surrounding areas. Fill the pond with lime and let it sit for 5-7 days, depending on the conditions.

Natural Water Coloring Techniques for Ponds

After pumping water with a water level of 0.5m, color the water in the pond. There are multiple methods, such as using soybean powder mixed with water and sprinkling it into the pond at a dosage of 3-5kg/100m2. Another method is to use NPK fertilizer.

Before adding water to the pond, filter it through a net to prevent impurities and unwanted organisms from entering.

Standards for Water Quality in Fish Ponds

• pH level: 7.0 – 8.0
• Dissolved oxygen (DO): > 4 mg/l
• Temperature: 25 – 30 degrees Celsius
• Amonia (NH3): < 1.0 mg/l
• Niterite (NO2): < 0.3 mg/l
• Transparency: 40 cm
• Hydrogen sulfide (H2S): < 0.01 mg/l

Stocking the Fish

It is advisable to stock the fish at a density of 20-30 individuals/m2 for a 6-month farming period. Before releasing the fish, soak them in saltwater for 15-30 minutes. The fish should be released in a similar manner to other fish. If transported in plastic bags, soak the bags in the pond water for a period of time before releasing the fish. Prior to releasing the fish, allow them to acclimate and adjust to the pH level of the water in the pond.

Feeding the Fish

Squarehead carp are omnivorous, with a preference for animal-based feed (shrimp, tadpoles, young fish, etc.). According to Ms. Le Thi Triet, a fishery promotion officer, squarehead carp can also eat rice bran, oil cakes, and cornmeal as supplementary food. When practicing deep-water farming, it is recommended to provide industrial feed with a protein content of 28-35%. When farming at a low density, processed feed should be used.

Feed the fish according to their growth stage:

• At 1 month old: Feed containing 35% protein, with a feeding rate of 5-7% of the fish’s body weight
• At 1-2 months old: Feed containing 30% protein, with a feeding rate of 4-6% of the fish’s body weight
• From 2 months until harvest: Feed containing 28% protein, with a feeding rate of 2-3% of the fish’s body weight

Previous Experience of Feeding Fish with Industrial Feed

This is the case of Ms. Lai Thi Thuong in Dong Thap Province who has invested in industrial feed to farm squarehead carp. She shared that she fed the fish with AFIEX brand feed for the first 30 days, combined with water fleas and existing phytoplankton in the pond. After one month, she continued to use the same feed but increased the amount and periodically supplemented the fish with vitamin C for a healthy development.

Although the cost is higher, the fish grow quickly, are less prone to diseases, have delicious meat, and can be sold at a high price.

Management and Care

Regularly replace the water in the pond, replacing only 20-40% of the water. If the water becomes dirty, it should be immediately replaced. Monitor the fish’s health, and if any abnormalities are observed, take appropriate measures. Squarehead carp are also susceptible to common fish diseases such as fungal infections, ulcers, etc.

After changing the water, add hydrated lime at a dosage of 1-2kg/100m2. Two days after adding the lime, use iodine or BKC to disinfect the pond water at a dosage of 1 liter/1500-2000m3 of water. After two days, use biological products with a dosage of 1000g/2500-3000m3 of water.

Harvesting Squarehead Carp

• Selective harvesting: Harvest fish that meet the market size, either using nets or manually catching them
• Complete harvesting: Harvest in November – December (Gregorian calendar) by using nets and draining the pond. Before harvesting, it is recommended to research the market prices.

After harvesting, clean and renovate the farming pond in preparation for the next successful season.

Preserving Squarehead Carp After Harvesting

Preservation using containers: Use containers such as foam boxes, plastic drums, or plastic containers that have been cleaned. Before placing the fish in the container, spread a layer of small stones (5-10cm) at the bottom of the container, then place the fish on top. Add another 5cm layer of stones, and repeat the process. The top layer should be stones, and then seal the container tightly.

Cold storage preservation: If you want to preserve the fish for a longer period of time, use cold storage. Clean and gut the fish, wash them thoroughly and let them drain, then place them in a plastic box with a lid or in sealed plastic bags.

The productivity of farming squarehead carp shows that the fish achieves high yields, shortens the farming time, and generates large profits for farmers. However, to avoid market fluctuations, farmers must have appropriate plans and strategies, farm according to the region, and avoid rushing to farm this type of fish excessively, which may result in difficulties in finding outlets.

See more: Farming Mekong Goby – A Famous Specialty of Quang Region