Black Ghost (Apteronotus albifrons)

Quick Facts :: Black Ghost Knifefish
Care Level: Moderate
Temperament: Peaceful
Maximum Size: 18″
Minimum Tank Size: 125 Gallons
Water Conditions: 75-84° F, KH 0-25, pH 6.0-7.5
Diet: Carnivore
Origin: Northern South America, Amazon
Family: Apteronotidae
Species: Knifefish
Aquarium Type: Ancient-Fish


The Black Ghost Knifefish (Apteronotus albifrons) is found widely distributed throughout the streams and rivers of the northern portion of South America. They are most commonly found in fast flowing jungle rivers and streams, but also move out into the flooded forests during the rainy season. They use their thin elongated body to move in and out of tree roots and dense vegetation, where they look for insects, insect larvae and small worms on which to feed. Black Ghost Knifefish are considered somewhat shy compared to most Cichlid species that inhabit the same Amazonian water ways. Hobbyists should keep Black Ghost Knifefish with tank mates that are not too boisterous or aggressive. Discus, Geophagus, Severum, Angelfish, peaceful Catfish, peaceful Cichlids and larger (6 inches or more) community species make good tank mates.

An ideal aquarium setup for keeping a Black Ghost Knife would be a 6 x 2 foot aquarium with sandy substrate, tree root, tall plants, moderate water flow and diffused lighting. Tank mates should be large enough to not be considered a food item, which is means they should be larger than 6 inches if kept with an adult Ghost Knife. Black Ghost Knifefish do well in fairly heavily planted aquariums and aquariums with tree root structures large enough for them to swim through. Ideally the aquarium should also have open swimming areas and areas of plants and root structure where the bright aquarium lighting is diffused. This will give the Knifefish a place to retreat to when it feels threatened or simply would like to escape the bright aquarium lighting. A wide variety of tank mates ranging from peaceful Cichlid species to larger community species can be kept with the Black Ghost Knifefish. Hobbyists looking to keep multiple Black Ghost Knifefish should have a larger aquarium (180 gallon or more) in order to have enough territory for multiple specimens to coexist peacefully. In a large aquarium, 4 or more specimens will be easier to keep than a pair as aggression will be spread out amongst the group instead of a single dominant specimen picking on a weaker one. As with other river fish species, clean water and low nutrient levels is critical to the long term health of this species. Due to the large size of this species, a quality canister filter or wet dry filter is recommended along with periodic partial water changes.

Black Ghost Knifefish (Apteronotus albifrons) are carnivores that prey mostly on insects and small worms in their native habitat. Aquarium specimens can be fed both live and frozen blood worms, tubifex worms or other similar meaty items. They can also be converted to eating other meaty foods like prawns, krill, earthworms, crickets etc. Some hobbyists have had success in getting them to eat commercial dry foods like pellets and sticks. They should be fed daily an amount of food that they will consume with a few minutes. It is best to vary their diet so that they receive all the vitamins and minerals that they need in order to maintain a healthy immune system.