The black ghost knifefish is a freshwater fish native to the Amazon River basin in South America. It is known for its elongated, ribbon-like body and dark coloration, which can appear almost black. This species can grow up to 20 inches long and is recognized for its unique swimming style, using its long dorsal fin to glide gracefully through the water. These fish are nocturnal and primarily feed on small invertebrates and other fish. They possess electroreception abilities, allowing them to detect electrical signals in the water, which helps them navigate and hunt in their dark, murky habitats.