In Phuoc Thoi ward, Can Tho city in southern Vietnam, aquaculture operator Huynh Van Tuan (42) got the artificial breeding of ca cuong (scientific name Lethocerus indicus) onto a stable track in seven tanks set on a 250-square-meter site. The local paper Dan Viet reported it on July 23, 2026. A male fetches 50,000 dong each, a female 20,000\u201325,000 dong, seed 100,000 dong, and eggs 90,000 dong per cluster (converted at 1 yen = about 162 VND, as of July 2026; 50,000 dong is about 310 yen). This insect is a material that has been used as a flavoring ingredient dripped a drop at a time into Hanoi's banh cuon or into fish sauce, positioned closer to a spice than a delicacy. The point for Japanese procurement is that its scent is shifting from wild collection to farming, becoming a raw material whose intensity can be specified by rearing conditions.<\/p>\n
According to Dan Viet, Tuan's rearing cycle is about 65 days, during which the ca cuong molts five times. Females are taken out at 65 days, and only the males are moved to a separate tank and reared on until around 75 days. The division is for the scent. The longer a male is reared, the better its form becomes, and beyond 90 days its essential oil grows richer in flavor and stronger in pungency, the paper writes. One tank is about 6 square meters. Feeding starts with tadpoles and guppies about 10 days old and switches to fry as they grow.<\/p>\n
The profit structure is plain. By Tuan's calculation, the average investment cost per individual is about 10,000 dong (about 60 yen). If a male sells for 50,000 dong, a margin remains. But the yield is not light. An egg cluster has roughly 100 eggs, but a level where 30 adults remain after hatching and rearing is considered a success. Annual profit is reported on the scale of several hundred million dong (300 million dong is about 1.85 million yen), with sales centered on social media and e-commerce sites and buyers concentrated in the north.<\/p>\n
Dan Viet reports that ca cuong once appeared in abundance in the rivers and paddies of the Mekong Delta but has become unseen in the wild due to changes in weather and environment. In the north the situation is similar; in a 2021 article VietnamNet reported that in the north it has become almost uncatchable due to heavy pesticide use, with what circulates mostly brought in from Laos or the south. A study of its habitat registered on Vietnam's National Science and Technology Information portal (NSTI) also positions this species as \"a rare aquatic insect listed in Vietnam's Red Data Book\" and is advancing habitat research for conservation.<\/p>\n
When wild collection thins, the price of the scent jumps, and to that extent farming's economics stand up. The same order of origin-building occurs with medicinal-herb materials (From forest to field: Quang Ninh turns the medicinal root \"dia lien,\" limited by wild harvesting, into a cultivated crop<\/a>), and ca cuong is its aquatic version. What differs is that the origin is not tied to a particular mountain village. Because it works with 250 square meters, tanks, and a small pond to supply fry, entry is spreading even to the urban fringe.<\/p>\n To grasp the real picture of farming, the one case in Can Tho is not enough. Nguyen Huu Duc in Phuoc Thuan commune, Tay Ninh province, handles the same insect at a scale of 45 tanks. But here it centers on selling live specimens and seed,<\/strong> with no processed goods. Lining up the two shows that scale and sales design decide the shape of revenue.<\/p>\nLining up the figures of two origins<\/h2>\n