Featherback Knifefish

The Featherback Knifefish (Notopterus notopterus) is a member of the family Notopteridae, the knifefish or featherback group characterized by a blade-shaped body and a long fin running beneath it. It is native to freshwater rivers, canals, ponds, and floodplain wetlands across South and Southeast Asia, from India through Indochina. Smaller and plainer than its relative the Clown Knifefish, it lacks the bold row of eyespots seen in that species. It remains widespread and common throughout its native range, tolerant of a variety of slow-flowing and standing freshwater habitats.

Featherback Knifefish can be identified by the following traits:

• Laterally compressed, knife-shaped body with an arched, sometimes humped back
• A single long fin running beneath the body, merging into the tail fin
• Small, low dorsal fin set on the back
• Silvery-grey to bronze coloring, generally without bold markings
• Small, upturned mouth

The lack of large ocellated spots along the flank is the clearest way to separate it from the larger, similarly shaped Clown Knifefish, which shows a prominent row of ringed dark spots.

This species occupies a wide range of freshwater habitats including slow rivers, canals, ponds, swamps, and floodplain lakes across South and Southeast Asia, from the Indian subcontinent through Myanmar, Thailand, and Indochina. It favors still to slow-moving water with cover from vegetation, roots, or submerged debris, where it can rest during daylight hours. The species tolerates warm tropical water temperatures and moderate turbidity, and is often found in agricultural waterways and seasonally flooded rice-growing regions within its range.

Featherback Knifefish are mostly nocturnal, secretive fish that hide near cover during the day and become active after dark to feed on small fish, insects, and crustaceans. They swim using an undulating motion of the long ventral-to-tail fin, allowing slow, precise movement through vegetation as well as quick bursts to capture prey. Reproduction involves adults depositing eggs on submerged surfaces such as roots or debris, which are guarded by a parent until hatching. As a common, adaptable species, it plays a role as a mid-level predator within its native freshwater food webs.