Red-tailed Catfish

Phractocephalus hemioliopterus is native to the Amazon and Orinoco drainages and is one of the most visually dramatic freshwater fish available. Adults routinely exceed a metre in length and require tens of thousands of litres to thrive. Despite their fearsome reputation, they are opportunistic rather than actively aggressive toward tankmates they cannot swallow.

Juveniles are occasionally sold at 10–15 cm and are irresistible, but buyers must understand the long-term commitment. Growth is rapid in well-fed juveniles — a fish can exceed 50 cm within two years — and the species regularly lives 15–20 years. It is strongly advised that only facilities capable of housing an adult purchase this species.

Feeding is straightforward: meaty whole foods such as prawns, fish fillets, and large pellets are eagerly accepted. Live feeder fish should be avoided to prevent disease introduction. The Red-tailed Catfish is largely nocturnal and most active after lights-out, when it patrols the tank bottom with surprising speed.

Water: 20–26°C, pH 6.0–7.5, moderate hardness (5–15 dGH); regular large water changes essential. Tank: Minimum 2000L for a single adult; bare-bottom or coarse sand, minimal décor to maximise swimming space and ease cleaning. Feeding: Carnivore; prawns, fish fillets, mussel, large sinking carnivore pellets; feed 2–3 times per week for adults. Breeding: Not achieved in home aquaria; spawns seasonally in large river systems; no reported captive breeding. Compatibility: Keep alone or with other very large, robust fish it cannot swallow; will consume tankmates of any species that fit in its mouth.