Onychostoma – The shovel-jaw carps

Onychostoma is a genus of cyprinid fish found in eastern Asia and Southest Asia, with the first known species Onychostoma gerlachi. Etymologically, onychos means “nail” and stoma means “mouth”, and the fish in this carp Genus is generally called as the shovel-jaw carps.

In Vietnam, Onychostoma fish occur from North to South, but mainly in clean moving streams in mountainous areas. The genus Onychostoma fish are officially called cá sỉnh in Vietnamese, but local species may have different vernacular names, such as cá sỉnh (in northern Vietnam), cá mát (in northern parts of central Vietnam), cá niên (in southern parts of central Vietnam and Central Highlands), cá xanh (in Huế) or some other ethnic names like pa khính or srang.

Species

Onychostoma gerlachi is probably not native to Vietnam, but since it’s the first known species of the genus Onychostoma, so Onychostoma species in Vietnam can possibly be mislabeled/misidentified as Onychostoma gerlachi.

Onychostoma babeense

Found in the fresh water and its distribution is Ba Bể Lake, Bắc Kạn Province, in northern Vietnam.

Onychostoma elongatum

Found in the waters of Ngòi Thia River, at Nghĩa Lô, tributary of Red River upstream of Yên Bái province in northern Vietnam. This species is considered as a local delicacy.

Onychostoma fangi

Found in Thác Bà Lake, in Lục Yên disctric of Yên Bái province.

Onychostoma ovale

Found in sông Bứa, Phú Thọ province, northern Vietnam.

Onychostoma uniforme

Found in Nà Rì River, Bắc Kạn province, northern Vietnam.

Onychostoma leptura

Found in Hòa Bình province, and some sources say several northern Vietnamese provinces like Phú Thọ, Lào Cai, Thanh Hóa, Hà Giang, Yên Bái.

Onychostoma laticeps

Found in Kỳ Cùng and Lam Rivers in Nghệ An province (northern part in central Vietnam). Possibly, it’s the same species in Quảng Trị and Huế.

Onychostoma meridionale

Found in the Se Bangfai River, Sekong River (Laos), Sesan River (Cambodia), Sa Thầy River-tributary of the Sesan River partly in the Vietnam’s Central Highlands to the Tonle Sap River (Cambodia).

Onychostoma krongnoensis

Found in Krông Nô River (the upper Srepok River) in Vietnam’s Central Highlands.

Onychostoma dongnaiensis

Found in middle Dong Nai River on the Langbiang Plateau, southern Vietnam.

Aquaculture

Studies on shovel-jaw carp aquaculture has been conducted in Vietnam since many years ago, but only show some successful results in recent years. Onychostoma sp. is now farmed in a modest scale in Kon Tum province.

Culinary uses

Nghệ An

Lunar August (the 8th lunar month) is the start of fishing season. The shovel-jaw carps are found primarily in Giăng River, as well as in some small rivers like Huồi Tắm River. They are considered as both healthy and nutritious, its meat is delicious, fatty, with little bone. The most delicious part of the fish is the head because the head is very soft, and the head bones can be eaten. The shovel-jaw carps are also believed to have beneficial effects on women’s breastfeeding, on reducing cardiovascular problems, and is very suitable for the elderly.

One common dish is braised fish. Firstly, the fish are fried with sauteed Asian shallots. Next, they are slow-braised with pound garlic, chopped chili, and ground black pepper, fish sauce and local Nam Đàn fermented soy bean sauce. Alternately, the fish can be pan-fried and are served with a dipping sauce made of that same fermented soy bean sauce.

If shovel-jaw carps are caught in large quantities, the locals often grill them. The fish are grilled by using a bamboo clip or a bamboo skewer over hot charcoal. The dipping sauce is ginger fish sauce.

Also, the fish can be used in a local fish soup called cá mát nấu trôi. The cooking method is simple: In a pot of hot water seasoned with hot pungent spices, the fish are added and get cooked.

Quảng Trị

The shovel-jaw carps are found in the streams of Đakrông and Hướng Hóa districts where the fishing season only lasts from about February to May of the lunar calendar. The cooking method is mainly from the Bru-Vân Kiều and Pako-Vân Kiều ethnic people.

The fish can be grilled and smoked to be used as a preserved food. The dipping sauce for the grill fish is very special. It is made from the fermented cooked fish intestines, which make the condiment slightly bitter. The other ingredient is chili pepper.

But the most unique condiment is called cheo cá mát. The condiment is made of pound coarse salt, chili pepper, ground shovel-jaw carp meat, and Zanthoxylum pepper (Zanthoxylum rhetsa, similar to Sichuan pepper). Cheo cá mát can be made from either fresh or dried fish. Traditionally, from fresh fish, the first step is to eliminate the muddy smell of the fish, the Vân Kiều people have devised a way to cook. They bring a pot of water with green tea leaves to a boil, and then pour into the pot. After about five minutes, they take them out to scale and remove the intestines. Next step is to remove the rib bones, and the Vân Kiều people use a knife to cut a vertical line from the gills to the bottom of the fish’s tail, removing all two rows of rib bones. And then they removes the tine bones left on the fish fillets. Finally, the fish fillets are ground with other spices. Alternately, the fish meat can be prepared from dried or freshly-grilled fish.

In Quảng Trị, Vân Kiều and Pa Ko people often use cheo cá mát condiment on xôi (sticky rice). The condiment is also commonly paired with roasted pork or boiled chicken.

Quảng Ngãi, Bình Định and other Central Highlands provinces

The Onychostoma fish in called cá niên in these provinces, and found in a few mountainous and midland districts such as Sơn Hà (Quảng Ngãi province), An Lão, Vĩnh Thạnh ( Bình Định province). These shovel-jaw carps can be grilled, cooked with bitter melon, with rau răm (Vietnamese coriander) leaves or deep-fried. Onychostoma fish intestines are even considered as an aphrodisiac.

Grilled shovel-jaw carp is a common dish. The condiment for this is made from ground coarse salt, bird’s eye chili and white basil leaves. Sometimes the fish are also steamed and served with the same condiment.

In Quảng Nam province, shovel-jaw carps are found in the streams of mountainous areas, inhabited by Cơ Tu, Xê Đăng, and Ca Dong ethnic people. Grilled Onychostoma fish is paired with a condiment made from anchovy fish sauce and turmeric, as well as several additional spices. Another notable dish is an Onychostoma fish sour soup with lá giang (Aganonerion polymorphum) leaves, and bamboo sprouts.