The vast archipelago of Indonesia, with its more than 5,590 rivers and thousands of lakes, provides fertile ground for a thriving freshwater aquaculture sector. Among the myriad species cultivated in these waters, one has emerged as a star performer for fish farmers: Pangasius hypophthalmus, known more commonly to Indonesians as 'patin siam'.

Originally native to the major river systems of Thailand, particularly the Chao Phraya and Mekong Rivers, the species was introduced to Indonesia in the early 1980s. Since then, it has been intensively cultivated in regions such as South Sumatra, Jambi, Riau, South Kalimantan, and West Java. Its remarkable adaptability to artificial environments and rapid growth have cemented its status as a leading national aquaculture commodity.

According to data from the Ministry of Marine Affairs and Fisheries (KKP), Indonesia's production of 'patin' catfish exceeded 400,000 metric tons in 2024, with Pangasius hypophthalmus being a primary contributor. This figure represents a significant increase from previous years, reflecting robust market demand for both domestic consumption and export. Beyond being sold as fresh fish, it is processed into value-added products like frozen fillets, nuggets, fish balls, and shredded fish floss.

In international trade, the fish is commonly known as the 'Sutchi catfish' or 'Siamese shark'—a nod to its streamlined, shark-like body. Globally, Vietnam stands as the leading exporter of this species, with exports valued at over $1.6 billion USD in 2022, primarily destined for the Chinese market.

Origin and scientific classification

Taxonomically, Pangasius hypophthalmus is classified as follows:

• Kingdom: Animalia
• Phylum: Chordata
• Class: Pisces
• Order: Siluriformes
• Family: Pangasidae
• Genus: Pangasius
• Species: Pangasius hypophthalmus

While P. hypophthalmus is the most intensively cultivated, it is part of a broader family with deep roots in the region. Indonesia is home to a significant diversity of 'patin' species, with at least 13 distinct species documented in its freshwater systems, from major rivers like the Musi and Mahakam to the lakes and swamps of Sumatra, Kalimantan, and Java. This diversity underscores the ecological and economic importance of the Pangasius genus within Indonesia's freshwater ecosystems.

Pangasius catfish caught from the Mahakam River: Luhkan Mahulu/Derris Hidayatullah

Morphology

Morphologically, Pangasius hypophthalmus has a distinctive and easily recognizable appearance. Its elongated body is smooth and scaleless—a characteristic of the order Siluriformes, or catfish—and features a silvery-white base color that darkens to a grayish-blue on its back. This lack of scales contributes to its resemblance to other catfish, although it belongs to the Pangasidae family, which is distinct from the Clariidae family of true walking catfishes.

A key feature is the presence of two pairs of barbels at the corners of its mouth. These act as highly sensitive sensory organs, crucial for detecting food in murky or low-light conditions. This sensory acuity supports its behavior as a benthic feeder, an organism that forages on the bottom of water bodies, consuming organic debris, aquatic insects, and plankton.

In the wild, Pangasius hypophthalmus can reach an impressive length of 120 cm (nearly 4 feet) and weigh over 20 kg (44 pounds). In commercial aquaculture, however, it is typically harvested at a market size of 600 to 1,200 grams (approximately 1.3 to 2.6 pounds). This size is usually reached within a cultivation period of five to seven months, depending on feed quality, pond management, and stocking density.

The fish’s body structure includes a small, short dorsal fin and a symmetrically forked caudal (tail) fin. Its pectoral fins are equipped with a hard, sharp spine, known locally as a 'patil'. This spine serves as a formidable defense mechanism against predators but can also inflict painful injuries on handlers if the fish is not managed carefully during capture and transport.

Further analysis of its fin structure reveals a long anal fin with 30–33 soft rays, a ventral fin with 6 soft rays, and pectoral fins with 12–13 soft rays. These fins facilitate its agile swimming, although it naturally tends to inhabit the bottom of large rivers. The fish's mouth is positioned slightly downward (an inferior mouth), a morphological indicator that it feeds on the bottom rather than preying on organisms at the water's surface. This feeding habit also allows it to serve as a natural cleaner within its aquatic ecosystem, making sinking feed an effective strategy in its cultivation.

Natural habitat and behavior

In its native habitat, Pangasius hypophthalmus is typically found in large, slow-moving bodies of water, such as the edges of major rivers, estuaries, and lakes with muddy bottoms. The fish displays a preference for environments rich with natural structures like large stones, submerged tree roots, and crevices in the riverbed, which it uses for shelter. This need for refuge is tied to its nocturnal behavior.

As a nocturnal species, its primary activities, including foraging for food along the bottom, occur at night. During the daytime, it remains largely inactive, resting in shaded or dark areas. This behavioral pattern is a crucial consideration in aquaculture, influencing ideal feeding times and pond design—for instance, by providing artificial shelters or managing light exposure to reduce stress.

A particularly interesting habit observed in the wild is the fish's tendency to surface around dawn. This behavior allows it to gulp oxygen directly from the air, revealing a specialized physiological adaptation for survival in environments with low dissolved oxygen levels. This remarkable ability is one of the primary reasons the species is so well-suited for cultivation, even in water bodies with less-than-ideal quality.

The cultivation of Pangasius Hypophthalmus

A primary advantage of Pangasius hypophthalmus in the world of aquaculture is its exceptional ability to adapt to suboptimal aquatic environments. The species is renowned for its resilience to fluctuations in water quality and can even survive in water with relatively low oxygen content. This characteristic makes it highly suitable for cultivation in diverse systems, from traditional earthen ponds to modern, space- and water-efficient biofloc systems.

Selection of Pangasius hypophthalmus broodstock to be distributed as aid to Kampar Regency: BPBAT Sungai Gelam

However, while the fish is tolerant, achieving optimal growth and health is heavily dependent on maintaining water quality within recommended parameters. According to technical standards for aquaculture, several key factors must be monitored:

• Dissolved oxygen (DO); levels should ideally be maintained at 5–6 parts per million (ppm), though the fish can tolerate a minimum of 3 ppm. Persistently low oxygen can slow metabolism, induce stress, and reduce feed efficiency.
• Temperature; the optimal water temperature for cultivation ranges from 23–33°C (73–91°F), with the best results seen between 28–30°C (82–86°F). Temperatures that are too low can inhibit growth and weaken the immune system, while excessively high temperatures can speed up metabolism and accelerate the decomposition of uneaten feed.
• pH Level; another critical parameter is the water’s pH, which should be kept between 6.5 and 9.0, with an optimal range of 7.0–8.5. Water that is too acidic or alkaline can interfere with the fish's respiration and osmoregulation functions.
• Dissolved gasses and toxins; furthermore, dissolved carbon dioxide (CO₂) should not exceed 10 ppm, as it can impair oxygen uptake. Levels of free ammonia (NH₃) and toxic gases like hydrogen sulfide (H₂S)—byproducts of decomposing waste and feed—must be kept to a minimum, ideally below 0.1 ppm, to prevent stress and the risk of mass mortality.

Careful management of these environmental factors is the key to unlocking the full potential of this resilient and economically vital species.