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Black Ghost Knifefish

By | Last Updated: 10th June 2020

Black ghost knifefish, a part of the ghost knifefish family, is a freshwater species indigenous to different parts of South America. These nocturnal fish have an all-black body that makes them appear immensely attractive, and a sought-after choice for any aquarium. They can emit and obtain electric signals, using electric organs as well as receptors to track their prey and even communicate, thus being classified as weakly electric fish.

Black Ghost Knifefish

 Quick Information

Scientific NameApteronotus albifrons
Other NamesGhost Knifefish, black knife, apteronotid eel
OriginSouth America covering the Paraguay-Parana river area, Amazon Basin, and parts of Venezuela
TypeFreshwater fish
Conservation StatusNot recorded
Behavioral CharacteristicsShy, not too social, preferring to be on their own; could get aggressive with other knifefish species
School Size4 – 5
Physical TraitsFlat, elongated body in the shape of a knife; a long anal fin stretching from its stomach to tail; lacks a caudal and dorsal fin
Growth Rate (How fast do they grow)5 – 6 inches per year (12.7 – 15.2 cm), with these slow growers reaching their full size till the time they are 2
ScalesThey are devoid of scales
ColorsFull black body apart from two white rings on the tail, and patches of white on its nose that can at times extend to its back
Size (How big do they get)20 inches (50 cm)
LifespanApproximately 15 years
Sexual DimorphismThe males have a horse-like face and a thinner body than their female counterparts; besides their visible differences, females generate higher frequency EODs (Electric Organ Discharge) than males
Probable Diseases Ich and other skin infections
Approximate Price (How much is it for)$17 – 20
Black Ghost Knifefish Size

Tank Setup & Care Sheet Details

Care Level Intermediate to expert (not recommended for novice owners since they display sensitivity to water changes)
Tank Size80 – 90 gallons (303 – 340 liters) for a single fish

Water Parameters

pH Level6.0  – 8.0
Temperature73° to 82°F (23 to 28°C)
Hardness5 – 19 dGH
Aquarium  Water FlowHigh

Tank Ambience

Substrate TypeSand, small gravels, live rocks, crevices
Tank MatesCompatible with: Species of catfish, peaceful cichlids (such as keyhole cichlid, yellow labs cichlid, and bovilion ram cichlid), guppies, bichirs, rasboras, barbs, tetras, angelfish, discus, and corydoras

Incompatible with: Other black ghost fish species as well as snails and shrimps as this fish, could eat them
Suitable Position in the TankBottom


DietLive or frozen diet of  brine shrimps, black worms, and bloodworms, as well as flakes and pellets
Frequency 2-3 times a day
Black Ghost Knife Fish

Important Things to Know for Fish Keepers

  • Cover the fish tank with a tight lid as these fish are often known to jump out of the aquarium when overwhelmed
  • Make sure to give them sufficient space and proper hiding spots, without which they could turn aggressive.
  • Owners often complain of their black knife ghost fish missing suddenly with their whereabouts being challenging to trace. Under such circumstances, check the inside of your tank thoroughly, among the decorations. These shy fish often tend to remain concealed in some quiet corner. Also, check the outside, keeping their jumping abilities in mind.
  • Do not add tank mates for the black ghost knifefish with a size less than 6 inches, as the former could perceive the new additions as their food and get at them.
  • Do not panic if you see them upside down or to their side, as that is how they often lie in the tank. However, if they show other symptoms like restlessness or lack of appetite, it would require a veterinarian’s intervention.


Q.  Are black ghost knifefish species blind?

No, the black ghost knifefish are not blind, but they have do not have a properly developed eyesight since they mostly remain active at night. This is the reason why they use the electric field for tracking their prey and even communicating.

Q. How did the black ghost knifefish get its name?

The black ghost fish has ghost associated to its name as many South American natives believed that the souls of the deceased inhabited in them.

Q. Do black ghost knifefish have teeth?

No, the black ghost knifefish, like most other species, are toothless fish.

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