The Barred Knifefish is a beauty, but often mistaken for its close cousin the Centipede Knifefish!

The Barred Knifefish Steatogenys elegans is often confused with its relative the Centipede KnifefishSteatogenys duidae. Many times it will be imported and sold as the Centipede, which is not necessarily a bad thing. It is a less common species but since they are being sold as Centipede Knifefish, their price remains reasonable. If you are able to obtain an Barred Knifefish it may very well be at a bargain price!

This is a member of the Hypopomidae Family of Bluntnose Knifefish found in tropical South America. As a group they are also referred to as Grass Knifefish or Leaf Knifefish. The distinguishing feature of these fish is their snout, which is blunt and short rather than the tubular or elongated snout seen on many other types of knifefish. There are currently only three species described in the Steatogenys genus.

The Barred Knife Fish has irregular ‘zig zag’ type dark bands on a lighter tan background. Though it is quite similar in appearance to S. duidae it’s a bit larger, reaching about 11 1/2 inches in length. Some descriptive names it is known by are Mottled Knifefish, Elegant Knifefish and Tiger Knifefish.

The body of the Mottled Knifefish is long and flat, though more rounded towards the head. It becomes narrow towards the back until it finally terminates in a thin point at the rear. It has no dorsal fin but does have an extremely long anal fin that moves in an undulating motion. It also has an electric organ that generates a very weak electric field around its body. The electrical charges from this organ, along with its undulating fins allow it to navigate its habitat in a forward or backward motion. It also helps it identifying food and other objects in the water. Unlike other knifefish, this species is toothless.

Like the Centipede Knifefish and many of the other Knifefish, this fish requires good hiding places to feel secure. Unfortunately this means you may not see your fish except at feeding time. A good way around this problem is to use a clear acrylic or plastic tube as the hiding place. These fish have poor eyesight so they use electrical impulses as a sort of radar so even though the tube is clear, their radar tells them that they are in a secure place.

This is not a difficult knifefish to care for once it is acclimated. It makes a great addition to most community tanks. The Barred Knifefish is peaceful and will pretty much ignore other fish, though it may snack on small species. It does requires lots of good hiding places to feel secure. In a community tank it needs to be kept with other calm, non-aggressive fish as it is very sensitive to motion. Too much activity will discourage it from coming out to feed. It does best when kept with its own kind and that will help alleviate its shyness. A group of 3 is minimum, but a school of 6 or more can reduce aggression as these fish constantly tussle with each to establishing a pecking orderace.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Gymnotiformes (Knifefishes)
  • Family: Hypopomidae
  • Genus: Steatogenys
  • Species: elegans
Barred Knifefish – Quick Aquarium Care
  • Aquarist Experience Level: Intermediate
  • Size of fish – inches: 11.6 inches (29.39 cm)
  • Minimum Tank Size: 55 gal (208 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Moderately Difficult
  • Temperature: 71.0 to 78.0° F (21.7 to 25.6&deg C)
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Habitat: Distribution / Background

The Barred Knifefish Steatogenys elegans was described by Steindachner in 1880. The are found in South America throughout the Amazon River Basin. The species is listed on the IUCN Red List as Least Concern (LC). It has an extremely large distribution and is abundant across a variety of habitats with no known major widespread threats, Other common names it is know by are Mottled Knifefish, Elegant Knifefish and Tiger Knifefish.

The Barred Knifefish are found in a variety of habitats. They are found in swift moving shallow and deep waters of the Amazon and Orinoco rivers. These rivers are very nutrient rich. But they can survive in nutrient poor black-water rivers as well. They are able to live in very low oxygen water as well as high, and are commonly found in shallow lakes and flooded forests that are very low in oxygen. They tend to like to stay in dense floating vegetation or leaf litter. They can normally be found laying in leaf filled substrates to avoid predators. They feed on small crustaceans and larvae.

  • Scientific Name: Steatogenys elegans
  • Social Grouping: Groups
  • IUCN Red List: LC – Least Concern


The Barred Knifefish can reach up to 11 1/2 inches (29.4 cm) and has a lifespan of 15 years. It has a flat long body, fuller and somewhat bulkier towards the head but terminates in a thin point at the rear. It has no dorsal fin but does have an extremely long anal fin starting near the pectoral fin area. This fin can move in an undulating forward or backward motion. Its body color is tan to light brown with irregular ‘zig zag’ type dark bands. The dark irregular bands are broadly spaced along the entire length of the body.

This fish also has an electric organ which allows it to generate a very weak electric field around its body. The field helps with a variety of things such as identifying objects in the water, gives it spatial orientation, helps it to navigate, and helps it identify food. Males use an electric ‘stereotyped’ communication to court females.

  • Size of fish – inches: 11.6 inches (29.39 cm)
  • Lifespan: 15 years

Fish Keeping Difficulty

The Mottled Knifefish, like most of the other Knife fish, are not very hard to care for once you get through the initial period of getting them use to their new surroundings. Feeding these fish is the most difficult part of caring for them. They are nocturnal and mainly stay at the bottom to feed. They are very sensitive to motion and too much activity in the tank from hyper or aggressive tank mates will discourage them from coming out to feed.

  • Aquarium Hardiness: Moderately Difficult
  • Aquarist Experience Level: Intermediate

Foods and Feeding

The Barred Knifefish are carnivores. In the wild they are nocturnal, when the sun sets and throughout the night they feed on small crustaceans and larvae. In the aquarium this is a species that prefers smaller fresh or frozen foods such as bloodworms, brine shrimp, or other smaller sized foods. Freeze dried foods will sometimes be accepted. They may eventually be trained to eat freeze dried foods but will most likely never eat any type of flake food. They retreat when the other tank mates are in a feeding frenzy. Night time feedings are important and making sure that foods make it down to them before others take it.

  • Diet Type: Carnivore
  • Flake Food: No
  • Tablet / Pellet: Occasionally
  • Live foods (fishes, shrimps, worms): Most of Diet
  • Meaty Food: All of Diet
  • Feeding Frequency: Daily

Aquarium Care

The Barred Knifefish needs clear and pristine waters. These fish are very sensitive to water changes and the water should be tested often to assure that you will have a healthy fish. Weekly water changes of 30 – 50% are suggested.

  • Water Changes: Weekly – Do a 30 – 50% water change weekly.

Aquarium Setup

The Barred Knifefish will usually spend their time at or near the bottom of the tank. A large well planted tank with hiding places among rocks and drift wood along with open sandy areas for swimming and feeding are needed. These are one of the smaller knife fish but still need a good sized tank. A 55 gallon (208 l) tank is about as small as you would want to use, but as they mature they will need a larger sized tank, not measuring less then 50 inches in length and !00 gallons. Use a high quality filter and provide a moderate water current.

Rock structures and plants with long twisted roots make a great decor and offer hiding places for your knife Fish. But these fish do need a good amount of unobstructed swimming room as well. Clay flower pots make great caves for these fish so they have a safe place to take refuge. Some aquarists will use a clear tube for the fish to hide in. This makes it feel secure, but also the aquarist can see it. Soft sand is the best choice for substrate.

The Elegant Knifefish are nocturnal fish and appreciate subdued lighting with floating plants to break up any light. To get the most enjoyment out of this fish add some Moonlight LED lights to make viewing this fish easier as they will hide when normal tank lights are on.

  • Minimum Tank Size: 55 gal (208 L) – A 55 gallon (208 l) tank is about as small as you would want to use, but as they mature they will need a larger sized tank, not measuring less then 50 inches in length and !00 gallons.
  • Suitable for Nano Tank: No
  • Substrate Type: Sand
  • Lighting Needs: Low – subdued lighting
  • Temperature: 71.0 to 78.0° F (21.7 to 25.6&deg C)
  • Range ph: 6.0-6.5
  • Hardness Range: 2 – 10 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Bottom – The Barred Knifefish will usually spend their time at or near the bottom of the tank.

Social Behaviors

The Barred Knifefish are generally peaceful and can be housed with small to medium non-aggressive fish. They require good hiding places and will not do well with aggressive tank mates. The long, pointed tail just looks too appetizing to anything that’s the least bit aggressive. They are easily stressed by fish that get overly excited during feeding time. Fast moving fish in large schools are not recommended as they will put unneeded stress on the this fish. Many times causing them to retreat to caves and not eat, causing them to eventually starve.

These are gregarious fish and if kept singly they are extremely shy. Yet they are territorial if kept in inadequate numbers. As a group they will constantly squabble to establish a pecking order. A group of 3 is minimal, but 6 or more will help alleviate any single fish from being bullied.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species – conspecifics: Yes – Keep in groups as they are gregarious fish, but territorial if kept in inadequate numbers.
    • Peaceful fish (): Monitor – Though not aggressive, this fish will eat anything small enough to be considered a meal.
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Monitor – They ignore tank mates that are big enough to not be considered food.
    • Shrimps, Crabs, Snails: May be aggressive – In the wild, this fish hunts at night for worms, crustaceans, insects and snails.
    • Plants: Safe

Sex: Sexual differences

Sexual differences are unknown.

Breeding / Reproduction

It has not been bred in captivity.

  • Ease of Breeding: Unknown

Fish Diseases

The biggest issue with the Barred Knifefish is starvation and sickness caused by lack of nutrition. These fish are hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won’t have to deal with health problems or disease. They are sensitive to some fish medications such as copper and those containing formalin.

Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance. Because these fish eat live food, disease can be passed to them from their foods. Make sure to quarantine live food before feeding.

When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your fish the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish is more likely to acquire disease.

As with most fish the Elegant Knife are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Barred Knifefish are only occasionally available.