Notopteridae
Bony-tongued fishes with knife-like bodies and specialized swim bladders.
The Notopteridae, a family within the osteoglossiform (bony-tongued) fish group, are called featherbacks or knifefishes. They are found in freshwater and brackish waters across Africa and parts of Asia, including the west, south, east, and southeast. There are 11 species in four genera, split into two subfamilies: Xenomystinae, the African knifefishes, and Notopterinae, the Asian knifefishes.
These fish should not be mistaken for Gymnotiformes, the electric knifefishes of South and Central America. While both groups swim similarly and look alike at a glance, they are not closely related. Some larger species, particularly *Chitala ornata*, serve as food fish and occasionally appear in aquariums. The family name comes from Greek *noton* (back) and *pteron* (fin).
The earliest known fossil from this family is an otolith of *Notopteridarum*, dating to the Late Cretaceous of India, roughly 70.6 to 66 million years ago.
Featherbacks have slender, elongated bodies that give them a knife-like shape. Their caudal fin is small and fused with the anal fin, which runs most of the body’s length. When present, the dorsal fin is small and narrow, inspiring the name “featherback.” To move, the fish holds its body stiff and ripples its anal fin, propelling itself forward or backward.
Notopterids possess specialized swim bladders that extend throughout the body and, in some cases, into the fins. Though not highly vascularised, this organ can absorb oxygen from the air and produce sound by squeezing air through a narrow passage into the pharynx. At least some species build nests and guard their eggs until hatching.
The 10 species (the source lists 10, though the family contains 11) are arranged as follows:
Subfamily Xenomystinae (African knifefishes, African featherbacks) Genus *Papyrocranus*: *Papyrocranus afer* (reticulated knifefish), *Papyrocranus congoensis* Genus *Xenomystus*: *Xenomystus nigri* (African brown knifefish)
Subfamily Notopterinae (Asian knifefishes, Asian featherbacks) Genus *Chitala*: *Chitala blanci* (royal knifefish or Indochina featherback), *Chitala borneensis* (Indonesian featherback), *Chitala chitala* (Indian featherback), *Chitala hypselonotus*, *Chitala lopis* (giant featherback), *Chitala ornata* (clown featherback or clown knifefish) Genus *Notopterus* (bronze featherbacks): *Notopterus notopterus* (Southeast Asia populations), *N
- common_name
- Featherbacks and knifefishes
- number_of_species
- 11
- habitat
- Freshwater or brackish environments
- distribution
- Africa and West, South, East and Southeast Asia
- earliest_fossil
- Late Cretaceous of India, about 70.6 to 66 million years ago
- notable_species
- Chitala ornata (clown featherback or clown knifefish)
Lore & Background
The family Notopteridae includes 11 species of osteoglossiform fishes, known for their slender, elongated bodies that give a knife-like appearance. The caudal fin is small and fused with the anal fin, which runs most of the length of the body. Where present, the dorsal fin is small and narrow, inspiring the common name 'featherback.' These fish swim by holding the body rigid and rippling the anal fin to move forward or backward.
Notopterids possess specialized swim bladders that extend throughout the body and even into the fins in some cases. Though not highly vascularised, the bladder can absorb oxygen from air and also functions to produce sound by squeezing air through a narrow passage into the pharynx. At least some species prepare nests and guard the eggs until they hatch.
The earliest fossil evidence for the family is an otolith of Notopteridarum from the Late Cretaceous of India, dating to about 70.6 to 66 million years ago. The name Notopteridae derives from Greek noton meaning 'back' and pteron meaning 'fin.'
Reader's Guide
The Notopteridae are significant as a distinct family of bony-tongued fishes with a unique mode of locomotion and specialized physiology. Their knife-like body shape and undulating anal fin propulsion distinguish them from superficially similar but unrelated Gymnotiformes (electric knifefishes) of South and Central America. The family's fossil record extends to the Late Cretaceous of India, indicating an ancient lineage. A few larger species, particularly Chitala ornata, serve as food fish and occasionally as aquarium pets. The family's distribution across Africa and Asia reflects a historical biogeographic pattern, though the source article does not resolve the details of that history. Their specialized swim bladder, capable of air absorption and sound production, adds to their biological interest. The 11 species are organized into four genera under two subfamilies, reflecting a division between African and Asian forms. The family's common names—featherbacks and knifefishes—highlight their distinctive morphology.
Did You Know?
- The family Notopteridae contains 11 species of osteoglossiform fishes.
- Notopterids swim by holding the body rigid and rippling the anal fin to propel forward or backward.
- The earliest fossil of the family is an otolith from the Late Cretaceous of India, about 70.6 to 66 million years ago.
- The name Notopteridae comes from Greek noton meaning 'back' and pteron meaning 'fin'.
More in Freshwater Fish 1-19
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record