The reedfish is a master of two worlds, breathing air and slithering on land.

Nature · Published 3 October 2026 Swipe more like this →

In short: This eel-like African fish, also known as the ropefish, defies typical aquatic limitations. Equipped with both gills and lungs, it thrives in oxygen-poor waters and even ventures onto land to hunt. Despite its snake-like appearance and nocturnal habits, this elusive creature remains a fascinating, albeit threatened, member of the bichir family.

The reedfish, Erpetoichthys calabaricus, is the sole member of its genus and a unique relative of the bichirs. Native to the fresh and brackish waters of West and Central Africa—specifically spanning regions from the Ouémé River in Benin to the Sanaga River in Cameroon—it has evolved a distinct, elongated body. Unlike other fishes that lengthen by adding tail vertebrae, the reedfish achieves its snakelike form by doubling its precaudal vertebrae. It lacks the pelvic fins found in its sister genus, Polypterus, and possesses a dorsal fin composed of individual spines supported by single rays.

A defining feature of the reedfish is its pair of lungs, which supplement its gills. This dual-breathing system allows the species to survive in environments with low dissolved oxygen and even persist out of water for short periods. In the wild, these fish are nocturnal, hiding in dense vegetation by day and foraging at night for insects, crustaceans, snails, and small fish. Remarkably, they are known to voluntarily explore land, slithering like snakes to capture prey before returning to the water. This terrestrial behavior is rare among their relatives.

Despite their adaptability, reedfish face significant challenges. The IUCN classifies them as Near Threatened due to habitat loss caused by urban development, agricultural expansion, and the rise of oil palm plantations. While they are a common food source in local subsistence fisheries and a fixture in the aquarium trade, their survival is precarious. In captivity, they are notoriously difficult to keep, often jumping from tanks or entering pumps. Furthermore, while spawning has been observed in aquaria since the 1990s, there are no reports of captive-bred hatchlings successfully reaching adulthood, highlighting how much remains to be learned about this resilient yet vulnerable species.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• This living fossil breathes through a slit on its head
• The evolution of fish that mastered the land
• Why these ancient, air-breathing fish are masters of swimming both forward and backward
• The glass knifefish is a translucent, electric predator lurking in deep river channels.
• The toadfish is a singing, venomous, nest-guarding master of the ocean floor
• A Cretaceous mammal was caught in the act of hunting a much larger dinosaur.
• Why ancient Romans kept red mullet as pampered, bell-trained pets in private ponds
• Reptiliomorpha: The ancient bridge between water-bound amphibians and the masters of dry land.
• Did a mysterious, archaic-looking human population survive in China until the recent past?
• Why are these migratory, torpedo-shaped predators known as the garbage cans of the sea?
• The red-billed quelea is the most numerous undomesticated bird on the entire planet
• The reticulated giraffe is the tallest land animal, but its social life is surprisingly complex.

More in Vertebrates · More in Nature · Latest · A–Z · All topics