Longtail knifefish (Sternopygus macrurus)

Scientific name: Sternopygus macrurus Bloch & Schneider, 1801

The Longtail knifefish (Sternopygus macrurus) is a freshwater fish of the family Sternopygidae. In the aquarium it needs water at 22–28°C (72–82°F).

Longtail knifefish care at a glance

Temperature: 22–28°C (72–82°F)

Biology

Occurs in swamps, creeks, and river with lentic waters. Preys on small invertebrates, particularly the larvae of aquatic insects. Breeds before the start of the rainy season or during the rainy season, with a fecundity count of 6473 eggs. Males persistently defend their territory and apparently make electric signals rates and interruptions thereof to females passing by to draw in a spawning partner. Mature females' EODs are of higher frequencies than mature males. Plasma androgens modulate the EOD frequency during the breeding season. Embryos hatch on day 4; larvae begin to feed on day 11. The electric organ and electroreceptors are both present in the larva at the time of first exogenous feeding. Seems to reach sexual m

Source: FishBase, licensed CC BY-NC 4.0.

Species facts

Scientific name: Sternopygus macrurus
Family: Sternopygidae (Glass knifefishes)
Order: Gymnotiformes (Knifefishes)
Class: Actinopterygii (Ray-finned fishes)
Maximum length: 141
Environment: Freshwater;; pH range: 6.0 - 6.5; dH range: 4 - 15 benthopelagic
Climate: Tropical
Distribution: South America: Magdalena River basin; entire extent of the Amazon and Orinoco River basins below approximately 500 m elevation including Napo River of western Ecuador and Madre de Dios River of Peru; all drainages of the Guianas Shield; Atlantic drainages of northeastern Brazil; S?o Francisco River basin; Rio de Janeiro, Brazil; Paraguay-Paran? River basin.
Conservation status (IUCN): Not Evaluated
Threat to humans: Harmless
Uses: Fisheries: commercial; aquarium: commercial