Erpetoichthys calabaricus

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Erpetoichthys calabaricus, also called African Ropefish or Reedfish, is an impressive African fish recognized by its elongated, eel-like body. Despite its snake-like appearance, it belongs to the family Polypteridae, an ancient group of fishes capable of using atmospheric air. Native to West Africa, including the Calabar River in Nigeria, it inhabits calm, shallow and heavily vegetated waters. This wild-collected species, with generally intermediate availability in the aquarium trade, requires a tightly covered aquarium. Its flexible body and air-breathing ability make it an excellent escape artist.

General species description

Erpetoichthys calabaricus is a bottom-oriented and midwater predator that is most active at dusk and during the night. Its very elongated body allows it to move between roots, plants and submerged woody debris. The species has functional primitive lungs in addition to its gills, allowing it to use surface air when the water is low in oxygen. In an aquarium, it is usually peaceful toward tank mates that are too large to swallow, but it may treat smaller fish as prey. It appreciates shelters and subdued lighting. A perfectly fitted lid is essential because it can squeeze through surprisingly small openings. Its availability is moderate and variable, which adds to its appeal among aquarists looking for an unusual species.

Geographic origin and habitat

Erpetoichthys calabaricus is associated with coastal drainages in West Africa, with Nigeria as the reference country and the Calabar River as the origin river indicated here. Its natural habitat includes slow-flowing river sections, floodplains, swamps and marginal areas where the water may be dark or stained by organic matter. The substrate is generally made up of mud, fine sand and plant debris. Bank vegetation is dense, with grasses, emergent plants, roots and submerged branches. These structures provide shelter and create low-flow areas. In an aquarium, the goal should therefore be a calm, shaded environment rich in cover rather than a rocky layout exposed to strong current.

Precise location and local name

The most precise geographic reference provided for Erpetoichthys calabaricus is the Calabar River, in southeastern Nigeria, near the Calabar region and its coastal waterway network. The species is also reported from other West and Central African drainages, but populations should not be mixed without provenance information. The most widely used trade name is Reedfish, referring to its shape, which resembles a reed stem. African Ropefish is also common in English. The name Calabar snakefish may occasionally appear in aquarium literature. No reliable regional local name is retained here. For a wild specimen, keeping the collection data and stated locality from the supplier is good practice, especially for a species with intermediate availability.

Appearance and physical characteristics

Erpetoichthys calabaricus has a cylindrical, highly elongated body covered with small, resistant ganoid scales. Its coloration ranges from olive brown to yellowish brown, with a lighter underside and a generally discreet appearance that helps it blend into vegetation and debris. The dorsal fin is transformed into a series of separated finlets, a distinctive feature of Polypteridae. The pectoral fins are relatively well developed and help with precise movement through cluttered habitats. The head is flattened, with a terminal mouth suited to capturing animal prey. Tubular nostrils and spiracles complete its specialized anatomy. The species can reach approximately 40 cm as an adult. Its ability to breathe surface air is an important adaptation to warm, slow-moving and sometimes oxygen-poor waters.

General diet

Erpetoichthys calabaricus is mainly carnivorous and locates prey through its sense of smell and exploratory movements. In nature, its diet includes small fish, crustaceans, worms and other aquatic invertebrates small enough to swallow. In aquariums, suitable foods include frozen or thawed prey items, such as bloodworms, pieces of shrimp, krill or small fish intended for aquarium feeding. Sinking carnivorous pellets may be accepted after acclimation, but they should not be the only food. Feeding in the evening is preferable, when activity increases. Small tank mates are at risk if they can fit into its mouth, so tiny fish should be avoided. A varied diet offered in reasonable portions helps maintain good condition without unnecessarily polluting the water.

Essential data

• Origin river: Calabar River
• Local name used: Reedfish; African Ropefish
• Origin of the scientific name: The genus refers to a fish with a reptile-like appearance; the species epithet refers to Calabar.
• Etymology of the full name: Erpetoichthys comes from the Greek herpeton, reptile, and ichthys, fish; calabaricus means from Calabar.
• Common/vernacular names: African Ropefish, Reedfish, Calabar snakefish
• Family: Polypteridae
• Subfamily: Polypterinae
• Name pronunciation: er-PET-oh-ik-this cal-ah-BAR-ik-us
• Discovery: 1865, by Smith
• Maximum adult size: Approximately 40 cm
• Water temperature and pH: 24 to 28 °C; pH 6.0 to 7.5
• Waterway appearance and surrounding vegetation: Calm or slow-moving water, often stained, bordered by dense vegetation, roots and submerged branches.
• Typical tank mates: Pelvicachromis pulcher, Phenacogrammus interruptus, larger African tetras, similarly sized Synodontis, other robust non-aggressive fish.
• Temperament and behavior: Generally peaceful, discreet and mainly crepuscular or nocturnal; predatory toward small fish.
• Water depth: Shallow to moderately deep areas, especially along margins and near shelter.
• Sexual dimorphism: The male generally has a broader and thicker anal fin; sexing can remain difficult in juveniles.
• Bottom structure and flow: Mud, fine sand and plant debris; low to moderate flow.
• Specimen status: Wild-collected species.
• Rarity: Level 2 out of 3; intermediate availability in the specialty trade.

In your aquarium

To succeed with Erpetoichthys calabaricus, provide a spacious aquarium, a tight-fitting lid and plenty of bottom-level hiding places. Stable, warm, well-filtered water is preferable to strong current. Avoid fish small enough to be swallowed and offer a varied carnivorous diet, ideally in the evening. Because the specimen is wild-collected, gradual acclimation and careful observation during the first weeks are especially important.