Armoured Catfish of South America

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Onglets

Description

Distinguishing features

Armoured catfish, or loricariids, have evolved remarkable adaptations for life in the freshwater streams of South America. Their distinctive suction-cup-shaped mouth allows them to anchor securely to rocks and other surfaces, even in fast-flowing currents. It also helps them feed by scraping algae and organic debris from the substrate.

Their streamlined, hydrodynamic body enables them to live close to submerged surfaces, often near rocks or fallen tree trunks. They have a broad, rounded head and a downward-facing mouth.

Unlike most fish, loricariids have no true scales. Instead, their bodies are covered with rigid bony plates that form a protective armour — one of the most distinctive features of this group.

Their pectoral and dorsal fins are often equipped with spiny rays, while their well-developed caudal fin provides stability in fast-moving water.

Their coloration generally ranges from brown to grey, with spotted, striped, or marbled patterns that provide effective camouflage in their natural environment.

Some individuals have small barbels around the mouth, though these are less prominent than in other catfish species. All loricariids possess odontodes—small, tooth-like projections on the body and fins—used in social or territorial interactions.

Reproduction

Loricariids reproduce by laying eggs. The male selects a nesting site—often a cavity sheltered from the current—then attracts a female, who deposits her eggs there. Depending on the species and the size of the individual, she may lay between 50 and 300 eggs. After spawning, the male ensures proper aeration and guards the eggs until they hatch.

Some species are known for their territorial behaviour during the breeding season.

Sexual maturity varies among species but is generally reached between 1 and 2 years of age.

Diet

Armoured catfish are omnivores with detritivorous habits. They feed on algae, plant debris, and occasionally small invertebrates.

Here are some feeding specializations found among different loricariid species:

Adonis pleco (Acanthicus adonis) – Primarily herbivorous when young, this species becomes more carnivorous as it matures.
Golden pleco (Scobinancistrus aureatus) and Pará pleco (Peckoltia sabajii) – Specialized in scraping surfaces to extract microorganisms. Their suction-cup mouth allows them to feed efficiently on rocks, wood, and submerged surfaces.
Red-fin cactus pleco (Pseudacanthicus pitanga) and Sultan pleco (Leporacanthicus joselimai) – Feed mainly on animal protein, such as worms, invertebrates, and small snails.
Royal panaque (Panaque nigrolineatus) and Flash panaque (Panaqolus albivermis) – Have mouths specially adapted for scraping wood and roots. This particular diet, called xylophagy, depends on a specialized gut microbiota that enables the digestion of wood.

Predators

In their natural habitat, young loricariids fall prey to carnivorous fish, fish-eating birds, and caimans. Their bony armour provides effective protection, though it does not make them invulnerable.

Adults—especially larger species—have few natural predators.

Habitat

Armoured catfish are native to the river basins of South America, particularly the Amazon, the Xingu, and the Tocantins. They inhabit areas with moderate-to-strong currents, often settling on rocky or sandy bottoms and taking shelter among roots, crevices, or submerged wood.

Water quality is crucial for their survival: it must be well oxygenated, slightly acidic to neutral, and maintain stable temperatures between 24 and 30 degrees Celsius.

Ecology, behaviour

Loricariids are bottom-dwelling freshwater fish that play an important ecological role in “cleaning” substrates and in the turnover of organic matter.

Their behaviour is generally crepuscular or nocturnal, although they can be active during the day in calm environments. Some species are more social, while others may show aggression toward members of their own kind.

Social interactions are influenced by small, tooth-like structures—called odontodes—found mainly on the head and fins. Combined with their bony plates, these structures help protect them from physical attacks. Odontodes also serve as ornamental features, playing a role in individual recognition. They can be used in partner selection or as a visual display of dominance during confrontations.

French name

Plécostome adonis, plécostome sultan, plécostome cactus à nageoire rouge, plécostome solaire, panaque royal, panaque albivermis, plécostome du Parà

Scientific name

Acanthicus adonis, Leporacanthicus joselimai, Pseudacanthicus pitanga, Scobinancistrus aureatus, Panaque nigrolineatus, Panaquolus albivermis Peckoltia sabaji

Phylum

Chordata

Class

Actinopterygii

Order

Siluriformes

Family

Loricariidae

Life span

8 to 15 years

Status

Flash panaque: Endangered. The five other species have not been assessed (IUCN).

At the Biodôme

At the Biodôme, you can see seven species of loricariids in the river and flooded forest area of the Tropical Rainforest ecosystem. Here are a few key features to help you identify them:

Adonis pleco (Acanthicus adonis) – One of the largest loricariid species. Its black body is dotted with bright white spots that stand out in juveniles. Spiny and powerful, it tends to be solitary and territorial. Average length: 80 cm.
Sultan pleco (Leporacanthicus joselimai) – A small fish with a dark body speckled with pale spots. Males have well-developed odontodes on their cheeks. Primarily carnivorous and nocturnal, it prefers rocky areas. Average length: 15 cm.
Red-fin cactus pleco (Pseudacanthicus pitanga) – A sturdy, armoured fish with an olive-coloured body and striking red or orange fins. Its body is covered with several rows of spines. Primarily carnivorous and territorial. Average length: 30 cm.
Golden pleco (Scobinancistrus aureatus) – Recognizable by its many golden spots on a brown background, which become finer with age. This stocky fish has broad fins whose edges are vividly tinged with gold. It favours rocky areas and cavities. Average length: 28 cm.
Royal panaque (Panaque nigrolineatus) – Characterized by horizontal black stripes contrasting sharply with its beige-olive body. It inhabits flooded forests and river bends where driftwood tends to accumulate. Average length: 35 cm.
Flash panaque (Panaqolus albivermis) – A small loricariid with a dark brown body marked by pale lines. These distinctive patterns appear as irregular lines or elongated spots. This species feeds on wood (xylophagous). Average length: 13 cm.
Pará pleco (Peckoltia sabaji) – It has a light brown to beige body covered with irregular dark spots that provide excellent camouflage. An omnivore with a preference for plant matter, it is mainly active at dusk. Average length: 13–15 cm.

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