Redtail Catfish

The redtail catfish is a large member of the long-whiskered catfish family (Pimelodidae), native to the Amazon and Orinoco river basins of South America. It is one of the most recognizable freshwater catfish due to its bold two-tone coloration and vivid red-orange caudal fin. In the wild it can exceed 1.3 m and 40 kg, ranking among the largest catfish in its family. The species is a dominant predator within its native river systems, occupying deep channels, floodplain lakes, and river confluences. Due to its striking appearance and eventual large size, it is also widely known in the aquarium trade, though wild populations remain the primary reference for its natural history.

Key identification features:

• Broad, flattened head with a wide terminal mouth
• Dark brown to blackish dorsal coloration transitioning sharply to a cream-white belly
• Bright orange-red caudal fin and dorsal fin margin, the source of its name
• Three pairs of long sensory barbels around the mouth
• Stocky, elongated body with a small adipose fin
• Adults reach over 1 m, dwarfing most other pimelodid catfish The sharp black-and-cream body contrast combined with the red tail make it unmistakable among South American catfish.

Redtail catfish inhabit the main channels, deep pools, and floodplain lakes of the Amazon and Orinoco river systems in South America, including Brazil, Peru, Colombia, Venezuela, and Ecuador. They favor warm, slow-to-moderate flowing freshwater typically between 22-28°C and are most commonly found near submerged structure, riverbanks, and confluence zones where prey concentrates. During seasonal flooding they move into inundated forest and floodplain habitat to forage before retreating to deeper river channels as waters recede. Their large adult size requires extensive, unobstructed river habitat with abundant prey and deep refuge areas.

This species is a nocturnal, opportunistic predator that feeds on fish, crustaceans, and other aquatic animals it locates using its sensitive barbels in low-visibility water. Juveniles are more active foragers along banks and vegetation, while large adults tend to hold in deep pools and ambush prey. Redtail catfish are largely solitary outside of the breeding season and grow continuously throughout their long lifespan. As an apex-level predator within its native range, it plays an important role in regulating populations of smaller fish species. Reproductive behavior in the wild is not extensively documented but is believed to follow seasonal flood-cycle spawning typical of large Amazonian catfish.