Black Knife.

 This fish lives at the bottom of the sand and rapid streams of Brazil, Peru, Bolivia and Colombia. Black Knife - predator. It feeds on various crustaceans, worms and small rybёshkami. The length is 50 cm and 35-40 cm in the aquarium. The males are larger than females.

It has electric organ, which is used to capture food and repel enemies.

Black Knife - night solitary fish. During the day it hides in shelters.

Despite the fact that he is a predator, black knife can live in an aquarium with other large fish. The aquarium should be covered. The water temperature is 25-30 degrees Celsius. It requires good aeration and filtration.