Redtail Catfish

Fascinating facts about the Redtail Catfish

• A 56 kg (123 lb 7 oz) redtail catfish set the IGFA world record in 2010, proving just how massive this Amazonian predator can become. The fish was caught by Gilberto Fernandes in Brazil and still tops the list. It shows that, despite most individuals staying smaller, the species can reach trophy-size weights that rival many sport fish.
• Nearly two metres long, 1.8 m (5 ft 11 in), is the extreme length recorded for a redtail catfish, though most adults measure between 1.1 and 1.4 m (3 ft 6 in – 4 ft 6 in). That size translates to a weight of around 80 kg (180 lb) in the very rare giants. The spread between average and record size reminds hobbyists why a juvenile bought in a pet shop can outgrow even the biggest home tanks.
• Fossils from the upper Miocene place the redtail catfish’s lineage at least 13.5 million years old, with species like P. nassi and P. acreornatus documented from ancient Venezuelan and Brazilian formations. This deep history makes the redtail the sole living heir of a once-diverse genus. It highlights how a single survivor can carry a long evolutionary story into modern rivers.
• A mature redtail catfish needs a tank of at least 10,000 L (2,600 US gal) to thrive, and weekly feedings of live or dead fish are essential. Overfeeding is a common cause of death, so careful portion control is crucial. These requirements explain why the species is rarely kept by casual aquarium owners and is instead displayed in large public exhibits.
• Although native to the Amazon, Orinoco, and Essequibo basins, the redtail catfish has become invasive in Malaysia, now populating the Perak and Pahang Rivers. Human releases of aquarium juveniles have helped it establish far from its South American home. Its spread illustrates how the pet trade can unintentionally turn a charismatic fish into a potential ecological threat.

At a glance

About the Redtail Catfish

The redtail catfish, Phractocephalus hemioliopterus, is a strikingly colored giant of South America’s riverine world. Its brownish back gives way to yellow sides, while an orange-red dorsal and caudal fin blaze like a sunrise, sometimes echoed in the pelvic and anal fins. A broad head bristles with four pairs of sensitive barbels that double as chemical noses, guiding the fish through the twilight of its nocturnal hunts. Though it can reach a rare 1.8 m (5 ft 11 in) and 80 kg (180 lb), most individuals settle into a more modest 1.1–1.4 m (3 ft 6 in–4 ft 6 in). It roams the Amazon, Orinoco, and Essequibo basins, favoring large rivers, streams, and lakes, where it swims actively rather than lying in wait. Its diet is indiscriminate – any creature or fruit that fits its cavernous mouth, from fish and crustaceans to fallen palm nuts and even dry cat food in captivity. A surprising trait is its ability to click, producing warning sounds that echo through the water, a rare vocalisation for a catfish. In the wild, the redtail catfish is a nocturnal predator that becomes territorial, moving slowly along the bottom by day and striking under cover of night. Hatchlings face a gauntlet of predators – jaguars, giant otters, Orinoco and American crocodiles, caimans, and humans – but adults, with few natural foes, turn the tables as voracious, opportunistic hunters. Their reproductive strategy relies on external fertilisation, and they communicate via clicks to deter threats. While prized in public aquarium exhibits and the aquarium trade, juveniles are often sold far too small for most hobbyists, leading to releases that have seeded invasive populations in Malaysia’s Perak and Pahang rivers.

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