Black ghost knifefish

Apteronotus albifrons

FreshwaterFish

Care at a glance

Temperature: 75–82°F (24–28°C)
pH: 6.0–8.0
Adult size: 17.7 in (45 cm)
Minimum tank: 85 gal (320 L)
Temperament: Mostly peaceful
Social behavior: Solitary
Swim level: Middle
Difficulty: Difficult
Breeding: No record
Rarity: Rare
Origin: South America
Family: Apteronotidae

Overview

The black ghost knifefish is a large, night-active fish that hides by day and needs a long tube or cave it can back into for security. Keep it singly, as adults are territorial toward their own kind, and give it calm, medium to large tankmates rather than small fish it could eat after dark. Feed live and frozen foods such as bloodworms, blackworms, and shrimp in the evening. It has delicate, scaleless skin, so use soft substrate and pristine water. This fish grows long and needs a tank of at least 320 liters, larger as it matures.

In the wild

Apteronotus albifrons ranges widely through South American rivers, from Venezuela to the Paraguay and Parana system and the Amazon basin, where it lives in warm, softly flowing water near sunken wood and root tangles. Give it a dimly lit tank with plenty of shaded hiding places, soft sand, and steady, well-filtered water. Keep the temperature between 24 and 28 degrees Celsius and the pH from about 6 to 8. Stable, clean water is important for its bare skin.

Good to know

The black ghost knifefish belongs to Apteronotidae and is one of the largest aquarium knifefish, growing to around 45 centimeters. It swims by undulating a long anal fin, letting it glide forward and backward with equal ease. It is a weakly electric fish: an organ near the tail generates a continuous electric field that it uses to navigate and hunt in the dark, since its eyesight is poor. Captive breeding is rarely documented.

Did you know

The black ghost knifefish senses the world through electricity. It generates a weak electric field around its body and reads the distortions to find prey and feel its way through total darkness, so it barely relies on sight.