The Secret Life of Knifefish

Knifefish are a family of fish that contain about 50 species called the Apteronotidae in the order of Gymnotifromes. Found in Panama, South America and Asia they live in a wide range of freshwater habitats with more than half of the species living deep in rivers where there is little to no light.

In this article we are going to take a look into the life of 5 of the Knifefish species.

Clown Knifefish (Chitala ornata)

Image Source: The Florida Museum of Natural History

Also known as the Clown Featherback or Spotted Knifefish, this fish is nocturnal and will eat pretty much any fish or plant that will fit into it’s mouth. As babies, this species will stay in a school of it’s own kind. Once they are large enough they will go off on their own and become very territorial.

Image Source: Pet Supermarket Supplies

One of the most unique features of this fish – like other species who spend time in stagnant waters – it has the ability to breath air in order to survive when oxygen levels are low. This gives it the ability to survive in swamp areas.

Although this fish is commonly kept in the home aquarium, it reaches a maximum length of 3 feet and 3 inches. Which in most cases is unsuitable for the home aquarium. As a result, unfortunately, this fish has become the world’s most invasive species.

Image Source: Science Source

With a size of over 3 feet and an undiscriminating appetite, this fish being an invasive species is not a good thing for the environment that it ends up in. So unless you have a very large pond, it’s best to steer clear of this species if you are looking to add a Knifefish to your home freshwater aquarium.

Ghost Knifefish (Apteronotus albifrons)

Image Source: Science Mag

From the same family as the Clown Knifefish, this species has a very unique ability. A nocturnal species, this fish lives in dark waters and navigates its environment with electrolocation. With this unique ability the Ghost Knifefish is able to detect the electric fields of other species. It can also stun or ward off predators using this ability.

Image Source: Josh’s Fish YouTube Channel

They can reach up to 20 inches in length when full grown. This fish – oddly enough – does not have any scales. This makes it prone to infections and intolerance to unfavorable water conditions. In the wild they are found throughout the Amazon River from Venezuela to Paraguay to the freshwater basins of Peru.

Image Source: Coast Gem USA

It is commonly kept in the home aquarium where water conditions are required to be as stable and favorable as possible and the decorations, substrate, etc. needing to be smooth in order to avoid injury. It is also recommended to have a UV sterilizer installed on the aquarium that they inhabit for extra measure to avoid the possibility of infections occurring.

Sand Knifefish (Gymnorhamphichthys rondoni)

Image Source: Wikipedia

Found in freshwater bodies of water in South America, this fish is also known as the Tubesnout Knifefish. Inside of it’s fairly long snout, there are no teeth. Their snout is used to sift the sand in order to find food.

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Like the Ghost Knifefish, this species also has the electrolocation ability, however, it’s ability is considered to be weak as compared to the rest of the species who have it. They use this ability to both communicate with other knifefish and sense their surroundings.

This Knifefish spends a good amount of it’s time burrowed into the sand. So if it is kept in the home aquarium, it needs to have a substrate of fine sand in order to thrive. Also, since it is generally a docile species, it can easily be out competed for food. So target feeding will be necessary. In the wild this species keeps the sand beds of it’s environment clean.

Centipede Knifefish (Steatogenys duidae)

Image Source: Animal World

Also known as the Leaf Knifefish, this species in from the Bluntnose Knifefish family. It is on the smaller side for a Knifefish reaching only 8.25 inches for a max length. Like the Sand Knifefish, it also has a weak electrolcation ability.

Image Source: Dr. Tom Bailey

It is found in the Amazon, Orinoco and Essequibo river basins. They are typically found in floating meadows or leaf litter along the river basins feeding on aquatic insect larvae and small shrimp. These areas have low oxygen levels which this species has well adapted to.

Due to it’s small size and non-aggressive temperament and leaf life coloration and unique design, this species is commonly kept in the home aquarium.

Glass Knifefish (Eigenmannia virescens)

Image Source: J. de Lange

This unique Knifefish has a transparent body with a green hue which is where they get their other common name: The Green Knifefish. Like the Sand and Centepede Knifefish, this species also has a weak electrolocation ability. This is used to navigate as well as communicate with one another. They are found in South America and are omnivores.

Image Source: Arizona Aquatic Gardens

They are known to be social among their own species and have an interesting to watch regular communication by using their electrolocation ability. So the in the aquarium, it is recommended to have more than one. However, this species has a maximum size of 1 foot 4 inches so the habitat will need to be a fairly large one.

Image Source: Fish Index

Their bodies appear to be very stiff and lack a dorsal fin. Despite their physicality, they move around pretty efficiently and are know to be interesting to watch swim. They are a non-aggressive species however, in a school they will develop a hierarchy of dominant and submissive fish without injuring each other.

So the Knifefish are a pretty cool species that have electrolocation abilities that allow them to live in dark areas and communicate with one another. They have been kept in the home aquarium for a long time and it’s pretty obvious aside from their unique appearance why someone would want to do so despite their large size. However, it is important that we ensure that we can provide a suitable home for these species if we decide to keep them as pets. One of the most rewarding things about keeping an aquarium is the ability to peak into the lives of amazing marine species. However, when we do so we need to ensure that we can properly care for them for the duration of their lives and ensure that they are not just surviving but thriving.

What was the most interesting thing that you learned about Knifefish when reading this article? Let me know by leaving a comment below.

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