Secret to raising giant water bugs for essence and high profits

Unique giant water bug farm in Can Tho

The giant water bug is renowned for the distinctive aroma of its essence. While giant water bug farming is well developed in Northern Viet Nam, the species remains relatively unfamiliar in the Mekong Delta.

In Can Tho City, the giant water bug farm owned by Huynh Van Thuan (42 years old) in Phuoc Thoi Ward is considered the city's unique model and is delivering high economic efficiency. On an area of only 250 m², Thuan has set up seven giant water bug farming tanks. The remaining area is used for a tarpaulin-lined pond where he raises tadpoles as feed for giant water bugs.

"For a year before deciding to raise giant water bugs, I spent my time following online forums and gathering information. At that time, I was considering a range of species, such as pigeons, pet dogs, crickets, and coconut worms. Of all these, giant water bugs seemed the most suitable. With so few people raising them, I decided to experiment with the species without any intention of turning it into a long-term business," Thuan recalled.

After spending some time in the business, he realized the model held significant development potential if three major bottlenecks, which had challenged many other farmers, could be overcome. The first challenge was food. Unlike many other farmed species, giant water bugs feed exclusively on live prey such as tadpoles, sweetfish, and crickets. In the early days, Thuan built two cricket farming houses to secure a proactive supply of feed while also generating additional income from selling commercial crickets. However, maintaining the two production models simultaneously proved labor-intensive and required considerable space, so he decided to focus on raising tadpoles and sweetfish.

The second challenge was product output. According to Thuan, selling the product only within the local area or neighboring provinces offered virtually no consumption market. Restaurants and traditional markets had very limited demand. To develop the model, farmers must reach customers nationwide.

Today, Thuan's "Giant Water Bug – Taste of Alluvial Land" product is consumed widely through social media and e-commerce platforms. As a result, the giant water bug product from Can Tho City has built up a stable customer base in Northern Viet Nam.

The final bottleneck lay in the disparity in commercial value between male and female giant water bugs. According to Thuan, the market strongly favors males because they possess scent glands that produce the distinctive aromatic essence prized in many culinary dishes. Females, by contrast, are less well known and therefore command lower prices. To address this imbalance, he stepped up selling breeding pairs, including one male and one female, priced at VND 80,000–100,000/pair. The approach not only meets farmers' demand for breeding stock but also enhances the commercial value of female giant water bugs.

With these three challenges resolved, the farming model has entered a period of stable growth. Rather than expanding by adding more farming tanks, Thuan has maintained about 14 tanks while building linkages with other farmers.

He supplies fertilized eggs to local farmers and later buys their commercial giant water bugs. Male giant water bugs are purchased for VND 20,000–30,000/head, while females are priced at VND 10,000/head. According to Thuan, this model enables more households to participate in production while ensuring a stable output.

Thuan's farm currently supplies 500–600 giant water bugs each month, with males selling for VND 40,000–50,000/head and females priced at around VND 20,000/head. He also sells eggs for approximately VND 90,000/clutch.

Secret behind high profits

Giant water bug farming is not particularly complicated but requires the understanding of the species' behavior. Each farming tank covers about 6 m² and is constructed with a solid steel frame lined with tarpaulin. The top is enclosed with mesh netting to prevent the insects from flying away. Inside the tanks, in addition to algae and water hyacinths that provide shelter, Thuan places four-hole bricks to secure dry branches, which serve as egg-laying sites for the female giant water bugs.

After the females lay their eggs, the egg clutches are transferred to a separate incubation tank to prevent them from being damaged by adult bugs. According to Thuan, it takes only 6-7 days for the eggs to hatch. The key factor determining the hatching rate is maintaining adequate moisture.

The eggs are laid on pieces of tree bark, which must be kept continuously moist. If the bark dries out, the eggs become dehydrated, causing the hatching rate to drop significantly. According to Thuan, this is a critical technique. Without mastering it, many farmers fail despite receiving thorough guidance. Under normal conditions, the bark bearing the giant water bug eggs must be dipped in water about 8-9 times a day. On colder days, the frequency may exceed 10 times, as the bark tends to dry out more quickly.

About 12 hours after hatching, the young giant water bugs begin hunting for prey. At this stage, their feed is 10-day-old tadpoles or guppies and then gradually transitions to sweetfish. Over their 65-day growth cycle, giant water bugs molt 5 times. According to Thuan, they develop a particularly strong appetite from the third molt onward. This is also the stage when farmers must pay close attention to feed sources.

"A shortage of live prey, or prey of an inappropriate size, will cause the giant water bugs to bite and cannibalize one another, leading to high losses. A giant water bug egg clutch typically contains around 100 eggs. After incubation and rearing, producing about 30 adult insects from a single clutch is already considered a successful outcome," Thuan said.

At harvest time, Thuan drains the farming tank. Females that have reached 65 days of age are harvested first, while the males are transferred to another tank and reared until they are about 75 days old. Notably, the longer male giant water bugs are raised, the more attractive they become. If they are kept for more than 90 days, their essence develops a richer fragrance and a more pungent character.

After harvesting, the giant water bugs undergo a processing sequence that includes cleaning, salting, roasting, vacuum-sealing, and freezing. Thanks to this preservation method, they can be stored for up to a year while retaining their quality and distinctive flavor.

Thuan is continuing his research to extend the giant water bugs' breeding period during the cold season. From November to January, giant water bugs typically reduce or cease reproduction, resulting in an unstable supply of eggs.

Notably, the model’s initial investment is relatively modest. After a farming period of about 65 days, the average cost is only around VND 10,000/head. With stable market demand, Thuan's family earns annual profits of hundreds of millions of dong.

$1 = VND 26,490 - Source: Vietcombank.