Fish
Indian Knifefish
Notopterus notopterus
Origin: The Indian knifefish is widespread in South and Southeast Asia — from India and Pakistan to Indochina and the Greater Sunda Islands. It inhabits slow rivers, lakes, ponds, and backwaters with dense vegetation, including slightly brackish estuaries.
Also known as: Bronze featherback, Asian knifefish, Notopterus notopterus
Fact sheet
- Size
- 30 cm
- Lifespan
- 10 years
- Minimum tank size
- 400 L
- Temperature
- 24–28 °C
- pH
- 6–7.5
- Hardness GH
- 3–12 °dH
- Temperament
- Semi-aggressive
- Social behavior
- Solitary
- Swimming zone
- Middle, Bottom
- Diet
- Carnivore
- Jumps out
- Yes
- Eats plants
- No
Overview
The Indian knifefish is a large nocturnal fish with a distinctive knife-shaped body and a long, undulating anal fin running from chest to tail. This fin lets the fish glide gracefully both forward and backward. It is a solitary predator, active at dusk and night, that needs cover and subdued light. The Indian knifefish breathes atmospheric air and is quite hardy, but grows large and needs a big aquarium. It suits experienced keepers in a species tank or with large, calm companions.
Appearance
The body is strongly compressed, knife-shaped, silvery-grey with a bronze sheen and no prominent spots (unlike the spotted Chitala). The dorsal fin is small and feather-like; the anal fin is very long, merging with the tail and running the whole length of the belly. In the aquarium it usually reaches 25–30 cm (to 60 cm in the wild). The eyes are large, adapted to nocturnal activity.
Care
A tank of at least 400 L with a base of at least 150×50 cm, cover of driftwood, pipes, and large plants, a tight lid, and free air space for breathing. Temperature 24–28 °C, pH 6.0–7.5, hardness GH 3–12. Strong filtration, subdued light, and regular water changes are needed. Use soft substrate and dark decor.
Feeding
A predator, active at night. It takes live and frozen foods — shrimp, pieces of fish, earthworms, large insects, and bloodworm. Juveniles can be trained onto sinking carnivore pellets. Feed in the evening after lights-out. Avoid mammalian meat.
Compatibility
Territorial toward its own kind and toward similarly shaped fish; it treats small fish as food. Keep singly or with large calm companions — big barbs, cichlids, and catfish. In cramped quarters adults fight. A species tank or a spacious community of large fish is ideal.
Breeding
It rarely breeds in captivity. In nature spawning falls in the rainy season; the fish lays eggs on substrate or driftwood, and the male guards the clutch, fanning it with its fin. Home breeding requires a very large volume and stimulation through changing water parameters.
Fun facts
The long anal fin lets the fish swim forward and backward with equal ease. The Indian knifefish is an obligate air-breather that needs access to the surface. In its homeland it is also a food fish important to local fisheries.