Reedfish

The reedfish (Erpetoichthys calabaricus), also called the ropefish, is the sole living species in its genus and a close relative of the bichirs (family Polypteridae), an ancient lineage of African freshwater fishes with primitive lung-like breathing structures. It is native to swamps, marshes, and slow-flowing rivers of West and Central Africa, from Nigeria to the Congo basin. Its extremely elongated, snake-like body and small paired fins set it apart from most bony fishes and reflect its ancient evolutionary lineage, sometimes called a 'living fossil.' Reedfish are popular in the aquarium trade for their unusual eel-like appearance and hardy, adaptable nature in low-oxygen water.

The reedfish is unmistakable for its extremely elongated, rope-like cylindrical body, which lacks the typical fish silhouette entirely.

• Body color ranges from olive-green to grayish-brown, uniform or with faint mottling, paler on the belly
• Tiny, thread-like paired pectoral fins sit just behind the head
• A row of small separated dorsal finlets runs along the back instead of one continuous dorsal fin
• Small eyes and a pointed snout
• Grows to 35-90 cm, thinner and more uniformly cylindrical than eels or knifefish, which have flattened bodies and continuous fins

Its bichir-like scales are thick and bony, distinguishing it on close inspection from true eels.

Reedfish live in freshwater swamps, marshes, flooded forests, and slow-moving rivers across West and Central Africa, with a range spanning Nigeria, Benin, Cameroon, and into the Congo River basin. They favor warm, shallow, densely vegetated water with soft muddy or sandy bottoms and low water flow, often in seasonally flooded habitats with fluctuating oxygen levels. Preferred temperatures range from about 24-28C. Thanks to a paired lung-like swim bladder, reedfish can breathe atmospheric air at the surface, allowing them to survive in stagnant, oxygen-depleted water and even move briefly overland between pools during dry periods.

Reedfish are primarily nocturnal, secretive predators that spend daylight hours hidden among roots, debris, or dense vegetation, emerging at night to hunt. They locate prey, including small fish, insects, worms, and crustaceans, largely by scent and touch rather than eyesight, using sensory structures around the snout. Individuals are generally solitary and can be territorial, though multiple reedfish may coexist peacefully in a large enough space. As facultative air-breathers, they regularly surface to gulp air, an adaptation that lets them colonize low-oxygen swamps and floodplains that exclude many other fish. Little is documented about wild spawning behavior, though breeding is believed to occur during the rainy season in flooded vegetation.