Duckbill Catfish Care Guide - Tank Size, Diet & Breeding

The Duckbill Catfish, Sorubim lima, is a large South American pimelodid catfish named for its broad, flattened snout and distinctly projecting lower jaw. Its elongated body is generally silvery to pale grey, often marked by a dark lateral stripe and a darker back, while the fins may show subtle dusky shading. Long barbels help it investigate its surroundings and locate prey in cloudy water.

This is a primarily nocturnal predator that spends much of its time close to the bottom or cruising through open water. Despite its imposing adult size, it can be a relatively calm fish when housed with suitably large companions. Anything small enough to fit inside its mouth is likely to be treated as food.

In the wild, Duckbill Catfish inhabit flowing and slow-moving rivers, channels, lagoons and flooded forest environments. They are capable swimmers and often use submerged wood, shaded banks and turbid water as cover while ambushing smaller fish and aquatic animals.

The species is one of the larger members of the Sorubim group and is not a suitable choice for most community aquariums. Its unusual profile and predatory behaviour make it an interesting subject for public aquariums and very large, specialist freshwater systems.

Duckbill Catfish are native to tropical and subtropical freshwater systems of South America, including parts of the Amazon, Orinoco and Paraná–Paraguay basin regions. They occur in countries including Brazil, Peru, Colombia, Venezuela, Bolivia and Paraguay.

A single adult requires a very large aquarium of at least 1,000 litres, with a preferred footprint of around 250 × 90 cm or larger; substantially bigger quarters are needed for multiple adults. Use a secure, tightly fitting lid because this powerful fish can jump, and provide strong filtration with well-oxygenated water and moderate circulation. A soft sand substrate, smooth rocks, substantial driftwood and shaded retreats create a natural riverine layout, but leave generous open swimming space and avoid sharp decor that could damage the catfish’s delicate barbels.

Up to approximately 54 cm (21.3 in) in total length. Females generally grow larger and become deeper-bodied than males, although individual size varies.

Duckbill Catfish are carnivorous predators. Offer a varied diet of appropriately sized whole foods such as earthworms, prawns, mussel, fish fillet and quality carnivorous sinking pellets. Young fish can be fed more frequently, while adults need substantial but controlled meals rather than constant feeding. Feeder fish should be avoided because they can introduce disease and provide poor nutritional balance.

Suitable companions include other large, robust and peaceful South American fish such as mature large characins, sizeable peaceful cichlids, large plecos and compatible riverine catfish. Tankmates should be too large to swallow and should not be aggressive or excessively territorial. Avoid small tetras, livebearers, dwarf cichlids, shrimp and other small bottom dwellers, as well as fin-nipping species and highly aggressive cichlids. Duckbill Catfish may also prey on smaller members of their own species if there is a substantial size difference.

Duckbill Catfish are rarely bred in home aquariums. In nature, they appear to reproduce seasonally during rising water levels, with mature fish undertaking movements into flooded habitats or river channels to spawn. Successful breeding is thought to depend on very large quarters, excellent water quality, seasonal changes in flow and temperature, and abundant live food. The eggs are released into open water, and there is no parental care.

Females are usually larger and more robust-bodied than males once mature. Males tend to remain slimmer, but reliable external differences can be difficult to identify outside of mature breeding fish.