African brown knifefish
Nocturnal freshwater fish with a knife-shaped body and fused fins.
The African brown knifefish is the sole member of its genus within the Notopteridae family. It inhabits fresh water basins across central and western Africa, including the Nile and Congo systems. This nocturnal species uses a unique fin structure for precise movement and relies on sensory pits to navigate dark waters while hunting invertebrates.
- Only species in the genus Xenomystus
- Fused anal and caudal fins enable backward swimming
- Uses sensory pits to navigate in darkness
- Can produce barking sounds and breathe air
- Reaches up to 30 cm in length
What it is
This fish features a distinctive ventrolaterally flattened and elongated body that resembles a knife blade. It lacks a dorsal fin entirely. Instead, the caudal and anal fins are fused into a single skirt-like appendage running from the gill opening to the tail tip. This structure allows for efficient forward and backward propulsion. The pelvic fins are tiny and unused for movement, while long pectoral fins provide precise steering. Small scales give the body a smooth look, interrupted only by a prominent lateral line used for sensing vibrations.
Where it lives
The species lives in fresh water streams and lakes across several major African basins. Its distribution includes the Chad, Nile, Congo, Ogowe, and Niger river systems. It is also found in coastal river basins in Sierra Leone, Liberia, Togo, Benin, and Cameroon. These fish prefer quiet waters with abundant vegetation where they can hide and hunt effectively.
How it lives
As a nocturnal hunter, this fish avoids bright light and navigates using nerve-filled pits along its body. Large eyes provide excellent night vision. It often swims with its head down, using short barbels near the substrate to locate food. The diet consists of worms, crustaceans, insects, and snails. The animal can produce barking sounds and occasionally surfaces to swallow air. Young individuals may school, but adults become aggressive toward their own kind.
Breeding and life cycle
Reproduction involves females laying clutches of 150 to 200 eggs. Each egg measures approximately 2 mm in diameter. Specific details regarding parental care or spawning seasons are not provided in the available data.
Fish and people
Aquarium enthusiasts have kept this species for a long time due to its unusual appearance. It requires dim lighting because of its nocturnal nature. Keepers note that larger specimens may eat smaller tankmates due to their relatively large mouths. While young fish tolerate small groups, older individuals tend to show aggression toward conspecifics.
Questions people ask about African brown knifefish
Why does the African brown knifefish look like a knife?
Its body is ventrolaterally flattened and elongated. The dorsal fin is absent, and the anal and caudal fins are fused into a long skirt-like structure. This shape allows for precise movement and energy-efficient propulsion in both directions.
What does this fish eat in the wild?
It feeds on bottom-dwelling invertebrates. Its diet includes worms, crustaceans, insects, and snails. It uses short barbels near its mouth and acute night vision to locate prey near the substrate.
Is this fish suitable for community aquariums?
Caution is needed. While young fish can be kept in small groups, adults become aggressive toward their own kind. Their large mouths mean they may prey on smaller tankmates. They also require dim lighting due to their nocturnal habits.
Good reading and sources
- African brown knifefish on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "African brown knifefish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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