Redtail Catfish yellow tail (Phractocephalus hemiliopterus) — 5-6cm

Overview

Redtail catfish (Phractocephalus hemiliopterus) stands as one of the most spectacular yet demanding predatory catfish available for sale UK. This magnificent South American giant captivates aquarists with its striking red-tipped caudal fin and powerful, torpedo-shaped body. Native to the vast Amazon and Orinoco river basins, the red-tailed catfish represents the ultimate challenge for expert freshwater enthusiasts prepared to dedicate thousands of litres, years of commitment, and substantial resources to its care. While juveniles appear manageable at 5-10cm, this species reaches an extraordinary 120cm in length, transforming from an appealing youngster into a massive apex predator that will dominate any aquarium or indoor pond.

Appearance

The redtail catfish displays a robust, streamlined body built for powerful swimming and predatory strikes. Juveniles exhibit attractive grey-silver flanks with dark speckling, but the defining feature remains the brilliant orange-red caudal fin that gives the species its common name. The broad, flattened head houses small eyes and long sensory barbels that sweep backwards when swimming. As the fish matures, the body becomes increasingly muscular and barrel-shaped, with adults developing substantial girth. The dorsal and pectoral fins carry hard, sharp spines capable of inflicting painful wounds during handling. Coloration may intensify or fade depending on diet, water quality, and stress levels, with well-maintained specimens showing the most vibrant red tail coloration.

Natural Habitat

This catfish inhabits large rivers, flooded forests, and deep channels throughout the Amazon and Orinoco basins in South America. During high water seasons, Phractocephalus hemiliopterus moves into flooded areas to hunt smaller fish, while the dry season concentrates populations in deeper river channels and lagoons. The species occupies mid-water and bottom zones, using its excellent chemoreception to locate prey in murky, tannin-stained waters. Natural habitat features include submerged timber, overhanging vegetation, and sandy or muddy substrates. Water flow varies from slow backwaters to moderate currents in main river channels, always with high dissolved oxygen and stable tropical temperatures year-round.

Aquarium Setup

Housing a redtail catfish demands an aquarium or indoor pond of at least 5,000 litres—and realistically, substantially more for long-term success with adult specimens. The tank must be extremely robust, with reinforced glass or acrylic capable of withstanding the fish's considerable weight and powerful movements. Furnish the environment sparingly with large, smooth river rocks and heavy driftwood securely positioned to prevent collapse. Avoid gravel or sharp decorations that could damage the catfish's sensitive barbels or skin. A soft sand substrate works best, though many keepers maintain bare-bottom systems for easier maintenance. Lighting should remain subdued, and a tight-fitting, weighted lid is absolutely essential to prevent escape attempts, as this species is a notorious jumper. Ensure all equipment is protected or positioned outside the tank to avoid damage from the fish's size and strength.

Water Parameters

Maintain tropical temperatures between 24-27°C with a reliable heater system sized appropriately for the massive water volume. pH should fall within the slightly acidic to neutral range of 6.0-7.5, mirroring Amazonian conditions. While the species tolerates minor fluctuations, stability proves far more important than chasing exact numbers. Ammonia and nitrite must remain at zero at all times, with nitrates kept below 40 ppm through vigorous biological filtration and frequent, substantial water changes. Given the enormous bioload, expect to replace 50% or more of the water weekly, necessitating efficient water-changing systems. Dissolved oxygen levels must stay high, achieved through powerful circulation pumps and surface agitation. Hardness can range from soft to moderately hard without issues, provided acclimation is gradual.

Feeding

As a carnivorous apex predator, the redtail catfish accepts a varied diet of quality sinking carnivore pellets, whole or filleted fish, large prawns, mussels, earthworms, and other substantial meaty foods. Feed adult specimens 2-3 times weekly rather than daily, as overfeeding rapidly leads to obesity and severely shortens lifespan. Juveniles require more frequent feeding to support growth but must not be allowed to gorge. Avoid exclusive reliance on feeder fish, which provide poor nutrition and risk introducing disease. High-quality pelleted foods formulated for large predatory fish should form the dietary foundation, supplemented with frozen and fresh seafood. Remove uneaten food promptly to prevent water quality deterioration. Monitor body condition carefully—a healthy redtail catfish appears muscular but not bloated, with a slight taper from head to tail rather than a rounded, overfed profile.

Behaviour

Redtail catfish are intelligent, responsive fish that quickly learn to recognize their keeper and often approach the glass during feeding times. Juveniles may shoal loosely, but adults become increasingly solitary and territorial, especially in confined spaces. The species is predominantly nocturnal in the wild, though captive specimens adapt to daytime activity when food is offered. Swimming behavior alternates between periods of restful hovering near the bottom and sudden, explosive bursts of speed when hunting or startled. Aggression toward tankmates is primarily predatory rather than territorial—any fish small enough to swallow will eventually be consumed. Even large companions may be harassed or injured during feeding competition. This catfish produces a heavy bioload, and its vigorous feeding can be messy, requiring exceptional filtration and maintenance.

Tank Mates

Selecting compatible tankmates for a redtail catfish presents extreme challenges given its predatory nature and massive size. Only very large, robust species such as giant gourami, large pacu, similarly sized arowanas, or large armored catfish (Pterygoplichthys, large Megalodonia) stand any chance of cohabitation, and only in truly enormous systems exceeding 10,000 litres. Most aquarists eventually maintain this species alone or with minimal companionship. Absolutely avoid small fish, shrimp, crayfish, or any creature that fits into the catfish's cavernous mouth. Slow-moving or delicate fish will be consumed or injured. Even supposedly compatible large species may face aggression during feeding or territorial disputes. In practice, a species-only setup eliminates stress, reduces aggression, and simplifies husbandry for this demanding giant.

Breeding

Breeding Phractocephalus hemiliopterus in home aquaria is extraordinarily rare and effectively impossible for private aquarists. This migratory species requires vast spaces, environmental cues from seasonal flooding, and large groups of mature adults to trigger spawning behavior. Successful reproduction occurs primarily in commercial fish farms in South America and Southeast Asia, where enormous outdoor ponds and hormone treatments facilitate breeding. Attempting to breed this species at home is unrealistic given the space requirements, long maturation period, and complexity of simulating natural spawning conditions.

Why Buy from Tropical Fish Co

Tropical Fish Co provides healthy, carefully selected redtail catfish juveniles with expert guidance on the extreme long-term commitment required. We ensure all specimens are feeding well on prepared foods before dispatch and supply comprehensive care information covering growth expectations, housing requirements, and dietary needs. Our experienced team candidly discusses the challenges of keeping this magnificent but demanding species, helping you make an informed decision. With nationwide UK delivery using specialist livestock couriers, your fish arrives safely in insulated packaging with oxygen. We support responsible fishkeeping and encourage only those with appropriate facilities and long-term plans to consider this ultimate aquarium giant.