Brachyplatystoma rousseauxii

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Brachyplatystoma rousseauxii — Flavicans Steel Cat

The Brachyplatystoma rousseauxii, also known as Flavicans Steel Cat, is a large predatory catfish from the Amazon basin. Its elongated body, silvery coloration and long barbels make it an impressive species, but it is extremely demanding in captivity. This is a long-distance migratory fish that can travel through the river system between feeding grounds near the estuary and spawning areas far upstream. Specimens offered in the trade are wild-collected, and this species remains very rare among aquarists. Successful long-term care requires an exceptionally large aquarium, powerful filtration and a diet suited to a large predator.

General description of the species

Brachyplatystoma rousseauxii is a large predatory siluriform belonging to the family Pimelodidae. It occurs mainly in the major waterways of the Amazon basin and has a life cycle closely connected to river migrations. It moves between downstream feeding areas and spawning regions located much farther upstream. This strategy explains its presence in several Amazonian countries and its association with major channels rather than small streams. Its activity is generally greatest at dusk and during the night. In captivity, its growth, adult size and need for swimming space make it suitable only for specialized facilities. Its longitudinal migration and large-predator lifestyle are the key factors to consider before acquisition.

Geographical origin and biotope

The species originates from the Amazon basin, particularly Brazil, Colombia, Peru and other areas connected to the Amazon system. It inhabits large rivers, deep channels, confluences and areas influenced by seasonal changes in water level. Its habitat generally contains warm, fresh and well-oxygenated water, with sand, mud or fine gravel on the bottom. Banks may be bordered by flooded forest, submerged wood and dense riparian vegetation. Adults mainly use open areas offering steady current and an abundance of fish prey. In Brazil, Brachyplatystoma rousseauxii is strongly associated with the Amazon River and its major tributaries. Specimens offered in the trade are wild-collected fish.

Precise location and local name

Within the Amazon network, Brachyplatystoma rousseauxii occurs from estuarine areas and the lower Amazon to tributaries and Andean sections far upstream. It is therefore not restricted to a single locality; its range follows a vast river axis. In Brazil, the most common vernacular name is dourada or dourado, referring to its golden reflections. The name piramutaba is also used in some regions for large catfish of the genus Brachyplatystoma, although regional usage can vary. In neighboring countries, Spanish names such as dorado or doncella may be used depending on the region and the species being discussed. For aquarists, scientific identification remains essential because trade names may group several large pimelodid catfish together.

Appearance and physical characteristics

The body of Brachyplatystoma rousseauxii is fusiform, strong and clearly adapted to open-water swimming. The head is broad and somewhat flattened at the front, with a large mouth and several pairs of long sensory barbels. Coloration ranges from silvery gray to golden brown, with a paler belly and metallic reflections that are especially noticeable in adults. The fins are usually subdued, while the deeply forked caudal fin supports rapid movement. As in several large pimelodids, the lateral line is well developed and helps detect movement in water that may contain substantial suspended particles. The combination of a massive head, highly developed barbels and a deeply forked caudal fin identifies a specialized river predator.

General diet

In the wild, Brachyplatystoma rousseauxii is mainly piscivorous. Its diet includes various fish captured in channels, confluences and flowing water. Young fish consume prey proportional to their size, while adults take much larger fish. In aquaria, suitable foods include appropriately sized whole fish, shrimp, mussels and quality frozen preparations intended for large predators. Very fatty foods, feeder goldfish and prey from unreliable sources should be avoided. Meals should be spaced and carefully controlled to reduce obesity and water pollution. Oversized filtration is essential because high-protein meals quickly create a substantial organic load.

Essential data

• River of origin: Amazon River and major tributaries of the Amazon basin
• Local name used: dourada or dourado; piramutaba in some regional usage
• Origin of the scientific name: a genus name created for Amazonian catfish; the specific epithet honors Rousseaux
• Etymology of the full name: Brachyplatystoma comes from the Greek brachys, short, platys, broad, and stoma, mouth; rousseauxii honors Rousseaux
• Common/vernacular names: Dourada, Dourado, Flavicans Steel Cat
• Family: Pimelodidae
• Subfamily: Pimelodinae
• Name pronunciation: bra-kee-plat-iss-TOH-mah row-soh-OWK-see-eye
• Discovery: Francis de Castelnau, 1855
• Maximum adult size: up to approximately 192 cm
• Water temperature and pH: approximately 24 to 29 °C; pH generally 5.5 to 7.5
• Watercourse appearance and surrounding vegetation: large channels, confluences, steady current, riparian forest and floodplain vegetation
• Typical tankmates: Brachyplatystoma filamentosum, Pseudoplatystoma fasciatum, Phractocephalus hemioliopterus, Oxydoras niger, Arapaima gigas, Osteoglossum bicirrhosum
• Temperament and behavior: predatory, generally solitary, most active at dusk and during the night
• Water depth: deep channels and pools of large rivers
• Sexual dimorphism: difficult to distinguish visually in live specimens
• Bottom structure and flow: sand, mud or fine gravel; moderate to strong current depending on the area

In your aquarium

Keeping Brachyplatystoma rousseauxii is appropriate for public aquariums or exceptionally large private facilities. It requires immense volume, extensive swimming length, warm and stable water, and efficient circulation without creating dangerously turbulent areas. Prey must be high quality and offered in moderation. Since this is a very rare aquarium species collected from the wild, purchasing one requires serious consideration of its long-term housing needs. The best results depend on space, oxygenation, water quality and a carefully controlled piscivorous diet.