Ghost Knifefish Facts

Interesting ghost knifefish facts for kids

The Ghost knifefish, prominently found in several countries of South America, belongs to the family of ray-finned fishes Apteronotidae. The ghost knifefishes primarily originated in freshwater and deep waters but people usually keep them in aquariums. Around 89 species such as the black ghost knifefish (Apteronotus albifrons) and brown ghost knifefish (Apteronotus leptorhynchus) are from the ghost knife fish family. Megadontognathus, Platyurosternarchus, Sternarchorhamphus are a few genera of the ghost knifefishes.

Unlike most fishes, the ghost knifefishes don't have a caudal fin or tail fin and move with the help of an anal fin on the back. Another feature that differentiates the ghost knifefishes from other species is the 'electric organ discharge' or EOD through which the fishes communicate with each other. The scaleless fish is quite aggressive as well and prey on insect larvae and fishes. The International Union for Conservation of Nature has not evaluated the conservation status of the ghost knifefish yet.

Keep on reading to learn more interesting facts about the Ghost Knifefish. If you want to know more exciting information about different animals, check out kelpfish and black neon tetra.

Ghost Knifefish

Fact File

What do they prey on?

Crustaceans, fishes, shrimps, worms, frozen foods

What do they eat?


Average litter size?


How much do they weigh?


How long are they?

6-23 in (45-60 cm)

How tall are they?


What do they look like?

Black, brown, white, tan

Skin Type


What are their main threats?

Humans, big fishes

What is their conservation status?

Not Evaluated

Where you'll find them

Freshwater, aquarium


South America





Scientific Name






Ghost Knifefish Interesting Facts

What type of animal is a Ghost Knifefish?

A Ghost knifefish is a carnivore fish generally found in different parts of South America prominently in the Bolivarian Republic of Venezuela and Brazil. There are around 89 species and the black ghost knifefish (Apteronotus albifrons) and brown ghost knifefish (Apteronotus leptorhynchus) are the major species of the ghost knifefish. The fishes are known for the electric organ discharge or EOD.

What class of animal does a Ghost Knifefish belong to?

The Ghost knife fish belongs to the family Apteronotidae. They are of the Actinopterygii class and Ictiobus genus. The freshwater fish primarily prey on insect larvae, small fishes while those living in aquariums are fed frozen meat, brine shrimp, and fish food.

How many Ghost Knifefish are there in the world?

The exact population of the ghost knife fish is not known as of now but the species such as the black ghost knifefish (Apteronotus albifrons) and brown ghost knifefish (Apteronotus leptorhynchus) are widely distributed throughout the South American continent. From Venezuela, Parana River in Brazil, to Amazon Basin, the ghost fish can easily be found.

Where does a Ghost Knifefish live?

The black ghost knifefish (Apteronotus albifrons) and other species of the ghost knife fish are primarily found in the different regions of the South American continent. The fishes can easily be spotted in the rivers of Venezuela, Bolivia, Argentina, Brazil, Paraguay, and many more.

What is a Ghost Knifefish's habitat?

The ghost knife fish is a tropical freshwater fish and is majorly found in rivers and great lakes of South America. Many people also love to keep the black ghost knifefish (Apteronotus albifrons) as a pet and keep them in a large aquarium.

Who do Ghost Knifefish live with?

Species such as the brown ghost knifefish and black ghost knifefish (Apteronotus albifrons) are nocturnal and remain active during the night. Unlike other species, several species of the ghost knife fish are quite shy and solitary. But during the breeding period, the fishes come together. Also, the fishes don't accept other species of knifefishes as tank mates.

How long does a Ghost Knifefish live?

The ghost knife fish of the Apteronotidae family generally live around 9-10 years but a few species such as the black ghost knifefish (Apteronotus albifrons) live around 10-15 years.

How do they reproduce?

The black ghost knife fish (Apteronotus albifrons) or any other species of the ghost knife breed only after attaining maturity. The exact process of breeding in freshwater or rivers is not known. But the black ghost knifefish are bred in a fish tank, large aquarium, and ponds. Several water parameters such as the optimum breeding temperature, consistency are required for breeding. Also, the tank size should be large enough, placed in a dark location for the black ghosts, should have enough hiding places. Also, the water temperature should be exactly 27-degree Celcius. All these water parameters are required to make the female black ghosts safe. Without these vital parameters, the female would not lay eggs. Unlike other species, the ghost knife fish found in rivers usually prey on their own eggs after spawning and have no parental involvement with the eggs. People generally remove the adult ghost knife fishes after the process of spawning or mating.

What is their conservation status?

The International Union for Conservation of Nature has listed the fish species in the Least Concern category as the population of any species ghost knifefish such as the black ghost knifefish and the duckbill knifefish is not a subject of disquiet. The freshwater fish can easily be found in several countries of South America, prominently in Venezuela and Brazil. People also keep the black ghost knifefish in tanks.

Ghost Knifefish Fun Facts

What do Ghost Knifefish look like?

The Melanosternarchus belongs to the family of ghost knife fish is a small fish while the black ghost knifefish is quite large compared to other species of ghost knife fish. The former has a large mouth, delicate and thinner body while the latter has a black thick body with a white stripe on its nose which makes the fish quite fascinating. Unlike other fishes, black ghost knifefish, the Melanosternarchus, the duckbill knifefish, or any other species of the ghost knife have no scales on their body. They can come in black, brown, white, and tan colors.

These rare ghost knifefish facts would make you love them

How cute are they?

The ghost knifefish is one of the beautiful fishes of the South American continent. The black knife fish is one of the species in the family of ghost fishes. They are scale-less and move with the help of the anal fin. Most of the species of the ghost knifefish have delicate or slender bodies which makes them interesting to look at and quite elegant.

How do they communicate?

Like any other species, the ghost knifefishes communicate the same way. Generally, fishes communicate through their touch and some studies also reveal that by the darkening of the skin, and sense of smell these fishes communicate. A unique characteristic in the black ghost knifefish and other species of the ghost knife family is the use of electric organ discharges or EODs. Unlike other fishes, the black ghost knifefish receive and sense the electric impulse through which they can communicate with each other.

How big is a Ghost Knifefish?

There are around 89 species in the ghost knife fish family and there exist differences in the size and weight of every fish. Several fishes such as the Melanosternarchus fish and Adontosternarchus fish are around 6-10 in (15-25 cm) in length while species such as the black ghost knifefish (Apteronotus albifrons) are more than 19 in (50 cm) long. The black ghost knifefish is five times larger than a few species of catfish while the Sternarchorhamphus muelleri fish is 25 times larger than the Rasbora fish.

How fast can a Ghost Knifefish swim?

The exact speed of the ghost knifefish is not known at the moment but the black ghost knifefish is quite active during the nights. Most of the species such as the Sternarchorhamphus muelleri fish, Megadontognathus fish, and the bulldog knife fish are considered very fast as they are found in the tropical freshwater of the South American continent.

How much does a Ghost Knifefish weigh?

No such information regarding the weight of a ghost knife fish is available at the moment. Species such as the Sternarchorhamphus muelleri fish, and the black ghost knifefish are quite large in size and we can imagine their weight by their huge body.

What are their male and female names of the species?

There are no such names given to the male and female species of the ghost knife fish. People usually observe the eyes of the fish to determine the sex of the fish. The male fish have eyes on top of the head while the females have eyes on the front of their heads.

What would you call a baby Ghost Knifefish?

People often call a baby ghost knife fish an alevin. The term, Alevin is used to refer to the newly hatched babies or juveniles.

What do they eat?

The species of ghost knife fishes are found either in freshwater or in aquariums. The fishes are carnivores, the species found in rivers and lakes generally prey on small insects, fishes, crustaceans. While those living at homes and large aquariums are fed frozen meat, earthworms, small pellets, fish foods, planktons.

Are they aggressive?

A few species of ghost knife fish are smaller in size than most of the species found in South America. These fishes are also regarded as very shy and they even love to be alone. But if someone tries to provoke or come closer to them, the fishes can attack as well. The black ghost knife fish is quite large compared to other species of the ghost knife family has no teeth but a beak that can harm humans, especially kids. Also, these fishes become aggressive with other species of knifefish.

Would they make a good pet?

The ghost knife fish is often regarded as a peaceful fish of rivers and lakes but species such as the black knifefish or brown knifefish are semi-aggressive or aggressive with their tank mates. Many people throughout the world consider the fishes as pets. But before taking them home, several things should be kept in mind such as minimum tank size, proper water conditions, the diet, and more. It is suggested that the minimum tank size should be 100 gallons. Also, sand and fine gravel should be used to make a suitable environment for the fishes. The aquarium's water temperature should be around 27-degrees Celcius, the main purpose of maintaining such water conditions, and arrangements are to resemble the wet season of their natural habitat.

Did you know...

The electric eel is the cousin of the ghost knife fish.

The Bakken Museum, situated in the state of the United State, Minneapolis has a device that converts the electric signals of the black ghost knife fish into audible sounds.

A species of ghost knife fish, tamandua knifefish are found in whitish-pink color and the fishes are one of the beautiful species of ghost knifefishes.

Different types of Ghost Knifefish

There are several types of ghost knife fish and research states that there are around 89 species of ghost fishes. The bulldog knifefish, the black ghost knife fish, the duckbill knifefish, the brown ghost knifefish, and the Sternarchorhamphus muelleri fish are a few species of ghost knifefishes.

What fish can live with Ghost Knifefish?

Firstly, we need to understand that the ghost knifefish needs more space compared to other fishes. The size of the aquarium should not be less than 100 gallons as small and confined space makes the fish more aggressive. Also, it is suggested not to keep the fishes of the same species as they could turn wilder quite easily. People generally keep peaceful fishes such as corydoras, catfish, and discus fish with them as these fishes serve as a great companion to the ghost knifefish. People highly consider the corydoras as it is a smaller fish.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish including Cory catfish, or blue catfish.

You can even occupy yourself at home by drawing one on our easy goldfish coloring pages.



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