Polypterus delhezi

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Introduction

Polypterus delhezi, also called the Barred Bichir, is a prehistoric-looking African fish valued for its elongated body and series of dorsal finlets. This bottom-dwelling species inhabits slow or moderately flowing waters in the Congo Basin. It breathes with gills but can also take atmospheric air through a rudimentary lung. Its mostly nocturnal behavior, opportunistic predatory diet, and adult size require a spacious, tightly covered aquarium with plenty of shelter. The specimens offered here are wild-collected; availability is moderate rather than common.

General species description

Polypterus delhezi is a robust member of the bichir group, an ancient lineage of African fishes with a distinctive appearance. Its cylindrical body stays close to the bottom, while its pectoral fins provide surprisingly precise movement. The species is mainly active at dusk and during the night, although it may patrol during daylight when it feels secure. It tolerates a fairly broad range of conditions but requires clean, well-oxygenated water. The aquarium should provide substantial floor space, hiding places, and a tightly fitted lid, since bichirs are excellent escape artists. Tankmates must also be too large to be swallowed.

Geographic origin and biotope

Polypterus delhezi originates from the Congo Basin in central Africa, particularly the Democratic Republic of the Congo. It is associated with quiet areas of major rivers, side channels, floodplains, and river margins where the current slows. The water may be stained by organic matter, with light filtered by vegetation and submerged branches. The bottom is commonly made up of sand, mud, and plant debris, with roots or sunken wood in some areas. In an aquarium, a dark layout with shelters is more suitable than a brightly lit, empty tank. The offered population is wild-collected.

Precise locality and local name

Available geographic references associate Polypterus delhezi with the Congo River system in the Democratic Republic of the Congo, without assigning every commercial specimen to one single collection site. The English name Barred Bichir is the main common name used in the aquarium trade, referring to the dark body bars. No sufficiently established regional local name is retained here. In aquarium discussions, the scientific name therefore remains the most precise way to identify the species, especially when it is compared with other bichirs sold under similar trade names.

Appearance and physical characteristics

The body of Polypterus delhezi is elongated and cylindrical, covered with heavy bony scales rather than ordinary flexible scales. Its base color ranges from brownish gray to olive green, with several irregular dark vertical bars that explain its common name. The head is flattened, the mouth is terminal, and the tubular nostrils are prominent, while the pectoral fins are broad and mobile. The dorsal fin is divided into a series of small finlets, an unmistakable bichir feature. Young fish often show stronger contrast; coloration may become darker depending on lighting, décor, and stress.

General diet

Polypterus delhezi is a carnivorous and opportunistic predator that locates prey mainly through smell and the detection of movement. Its natural diet includes small fish, crustaceans, aquatic insects, and other bottom-dwelling invertebrates. In aquaria, suitable foods include sinking carnivore pellets, pieces of shrimp, mussel, marine fish, and clean earthworms. Meals are best offered as the lights dim because the species is primarily nocturnal. Food items must be sized according to the width of its mouth; any sufficiently small fish may be treated as prey.

Essential data

• Native river: Congo River
• Local name used: Barred bichir
• Origin of the scientific name: Polypterus refers to the bichir genus; delhezi is a specific name dedicated to a person named Delhez.
• Etymology of the full name: Polypterus means “many fins”; delhezi is a surname used as the specific epithet.
• Common/vernacular names: Barred Bichir; barred bichir
• Family: Polypteridae
• Subfamily: Polypterinae
• Name pronunciation: pol-ip-TEER-us - del-HEZ-ee
• Discovery: George Albert Boulenger, 1899
• Maximum adult size: About 44 cm
• Water temperature and pH: 24 to 28 °C; pH 6.0 to 7.5
• Watercourse appearance and surrounding vegetation: Slow to moderately flowing water, shaded areas, roots, branches, and abundant riverside vegetation.
• Typical tankmates: Polypterus bichir bichir, Erpetoichthys calabaricus, Synodontis schoutedeni, Phenacogrammus interruptus, Steatocranus casuarius
• Temperament and behavior: Generally peaceful toward fish too large to swallow; nocturnal and only mildly territorial.
• Water depth: Shallow to medium-depth areas near the bottom.
• Sexual dimorphism: Males generally have a broader, thicker anal fin; identification is more reliable in adults.
• Bottom structure and flow: Sand, mud, wood, and plant debris; low to moderate current.

For greater success

To keep Polypterus delhezi successfully, provide a long, spacious aquarium, a smooth substrate, several shelters, and a fully secured lid. Keep the water stable, offer sinking meaty foods, and feed preferably in the evening. Tankmates should be robust and too large to fit into its mouth. Efficient filtration, regular water changes, and access to quiet surface areas support long-term health. Because this is a wild-collected species, careful acclimation and quarantine are especially sensible practices.