The beautiful Clown Knifefish is probably the aquarist’s most favored species of knifefish!

It is a very popular knifefish. This is partly because of its common availability and being relatively inexpensive. But it’s also a favorite because it is extremely attractive. They usually have a pattern of large spots, but this can be quite variable and it seems that no two Clown Knifefish are exactly alike.

The normal coloring of the Clown Knifefish is a silvery gray characterized by a variable pattern of large spots above the base of the anal fin. Yet sometimes they may have no spots at all, and sometimes they may have two rows of smaller spots. Other common names it is known by are Clown Featherback Fish, Spotted Knifefish, Spotted Featherback Fish, and Clown Knife. There is also an albino color form as seen in the picture above that’s called the Albino Clown Knifefish.

The Clown Knife has the typical knifefish body shape, flat and elongated with an arched back. Its anal fin and caudal fin (tail fin) are joined, giving it a long continuous fin along the underside. This fin undulates, allowing it to move either forward or backward, making it a very graceful swimmer.

Clown Knife Fish are suggested for an aquarist with some fish-keeping experience. They can be hard to get adjusted to a new tank and this often results in death. This fish can grow to a substantial size, reaching about 3 1/2 feet (100 cm) in the wild. Specimens raised in the aquarium, however, generally won’t grow much larger than 10 – 20 inches (25 to 50 cm). This is still a large fish, but since they are not particularly active they do not need as large of a tank as you might think. An adult can be comfortably housed in a 200-gallon (757 l) aquarium. Being nocturnal they need places to retreat during the day as well as open areas for swimming. Once acclimated, they are very hardy fish.

It’s a member of the Notopteridae family which contains contains some of the more outgoing species of knifefish. They are generally peaceful and will do well with other fish that are not particularly aggressive and that are too large to fit into their mouths. Do take caution as they have poor eyesight and will sometimes try to eat bigger fish than they can handle. They can ultimately injury or kill a fish they are unable to eat.

Scientific Classification


Clown Knifefish – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:55 gal (208 L)
Size of fish – inches39.4 inches (100.00 cm)
Temperature:75.0 to 82.0° F (23.9 to 27.8&deg C)

Habitat: Distribution / Background

The Clown Knifefish Chitala ornata was described by Gray in 1831. They are found in South East Asia; Thailand, Laos, Cambodia, and Vietnam. The species is not listed on the IUCN Red List. These fish are in great demand in many of the regions they live in for food. Other common names they are known by include Clown Featherback Fish, Spotted Knifefish, Spotted Featherback Fish, and Clown Knife. The albino color form is known as the Albino Clown Knifefish.

This Spotted Featherback Fish inhabit lakes, swamps, and the moving backwaters waters of medium to large rivers. Young fish occur in schools among aquatic plants and submerged roots. Adults tend to be loaners, commonly found near shore in areas with overhanging vegetation or docks.They utilize air to survive in warm, stagnant waters with little oxygen.

More recently they have been popping up in the United States in warmer climates states like Florida. These fish are some times caught by anglers going after bass. They are starting to populate parts of the United States because of irresponsible fish owners setting them free when they can no longer care for these demanding fish. The largest fish reported in Florida was 36 inches long.

The C. ornata has a close relative Chitala chitala which comes from India and is also a common import. This species is also called the Clown Knifefish as wells as Royal Clown KnifeFish, Royal Spotted Knifefish and Spotted Featherback. The coloring and behaviors of these two are the same but the India species is said to get a bit larger, reaching up to 4 feet (122 cm). The C chitala is listed as more precarious on the IUCN Red List, and is considered Near Threatened (NT).

The authors of the book, Encyclopedia Of Exotic Tropical Fishes For Freshwater Aquariums, Glen S. Axelrod, Brian M. Scott, and Neal Pronek say these two are so similar that only a trained ichthyologist can distinguish between them, and that their taxonomical standing is in a state of confusion. It may turn out that C. ornata is synonymous with Chitala chitala in the near future.

  • Scientific Name: Chitala ornata
  • Social Grouping: Varies – Juveniles occur in schools but as adults they live alone.
  • IUCN Red List: LC – Least Concern – Although it is heavily utilized from the wild, at present there is no evidence of widespread population declines. It is has also been introduced for aquaculture in Myanmar and the Philippines.


The Clown Knifefish can reach up to about 3 1/2 feet (100 cm) and weigh about 11 pounds (5 kg) in the wild. Most tank raise specimens however, won’t grow much larger than 10 to 20 inches (25 to 50 cm). Its body shape is flat and elongated with an arched back. It has a continuous fin along the underside formed by a joining of the caudal and anal fin. This fin undulates, allowing it to move either forwards or back wards. It also has a very small dorsal fin.

Their overall body color is a silvery gray. Their most distinguishing characteristic is a variable pattern of large spots above the base of the anal fin. However, it seems that no two patterns are exactly alike. They may have no spots at all, and sometimes you may find one with two rows of smaller spots. The specimen pictured above is the albino color form.

  • Size of fish – inches: 39.4 inches (100.00 cm) – In the wild these fish can reach about 3 1/2 feet, but most tank raise specimens won’t grow much larger than 10 to 20 inches (25 to 50 cm)
  • Lifespan: 15 years – The Clown Knife fish has a lifespan of about 8 – 15 years in captivity.

Fish Keeping Difficulty

Clown Knife Fish are not suggested for beginners but rather for an aquarist with some fish-keeping experience. These fish are usually offered for sale at a size of 3 to 6 inches and many hobbyists have unknowingly bought a pet they weren’t prepared to keep. That cute little 3 inch fish can grow to over 3 feet long, but in an aquarium 10 – 20 inches is usually the maximum size. If you plan on keeping one for a long time in good condition, be prepared to setup a 200-gallon tank.

Juveniles can be sensitive to water conditions when they are smaller than 9 or 10 inches. Many young fish die soon after purchase normally due to shock or unsuitable tank and water conditions. They are very hardy fish once they reach a larger size. Like most Knife fish they are extremely shy and are sometimes hard to get to eat when introduced to a new tank.

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

Foods and Feeding

The Clown Featherfin Fish are carnivores. In the wild they are predatory animals, primarily piscivores, which means they mostly eat fish. In the Aquarium they prefer to eat fresh foods such as worms or small fish, but it is a good idea to do your best to condition them to eat sinking pellets or some other dried food of substance. This will make feeding them much easier and less costly.

When shopping for a Clown Knife, avoid fish that are under 3 inches or over 6 inches. The smaller ones are relatively delicate and the larger ones can be harder to get feeding.

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

Aquarium Care

This fish is scaleless and very sensitive to water condition changes as with most scaleless fish. A high quality filter is a must! Weekly water changes of 30 – 50% are needed. Water condition tests should also be done weekly to make sure levels are not spiking.

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

Aquarium Setup

Clown Knifefish will spend most of their time in the middle or near the bottom of they tank, but they may occasionally go to the surface to grab a gulp of air or a meal. This fish can reach an enormous size even in the home aquarium. They can be comfortable in a 55 gallon tank until they reach around 10″, but for the long term you will need a tank that is 200 gallons or more, and bigger is always better. Use a high quality filter and provide a moderate water current. A UV sterilizer is a smart thing to incorporate into your tank as these fish are very sensitive to medications. The UV sterilizer will kill many diseases.

In the wild they inhabit slow moving rivers and lakes in many areas of Asia, so do well in tanks set up similar to this type of environment. Due to their nocturnal nature they need a place to hide during the day. A piece of pipe or a cave where they can get away from the light works great. Without this, they can become stressed very easily and will try to fit themselves into any dark space they can find, often causing damage to themselves. They do better with open swimming space, but they are adept as negotiating obstacles such as plants and piles of rock.

They prefer a neutral pH and softer water, but larger fish can adapt to a higher pH and hard water. Provide them with well filtered water, a dimly lit tank and hiding places, and you should have a happy Clown Knife.

  • Minimum Tank Size: 55 gal (208 L) – A 55 gallon tank is fine for a juvenile, but they grow quickly and will soon need a tank that is 200 gallons or more for the adult.
  • Suitable for Nano Tank: No
  • Substrate Type: Any
  • Lighting Needs: Low – subdued lighting
  • Temperature: 75.0 to 82.0° F (23.9 to 27.8&deg C)
  • Range ph: 5.5-7.0
  • Hardness Range: 2 – 10 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Bottom – Clown Knifefish will spend most of their time in the middle or near the bottom of the tank, but they may occasionally go to the surface to grab a gulp of air or a meal.

Social Behaviors

They are generally peaceful but due to their large size, they will eat any tank mates small enough to fit into their large mouths. Don’t keep them with large aggressive fish, but large peaceful fish are okay.

  • Venomous: No
  • Temperament: Semi-aggressive
  • Compatible with:
    • Same species – conspecifics: Yes
    • Peaceful fish (): Monitor – While it is not necessarily aggressive, it will eat anything small enough to be considered a meal.
    • Semi-Aggressive (): Monitor
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Monitor
    • Large Aggressive, Predatory (): Threat
    • Monitor – They ignore tank mates that are big enough to not be considered food.
    • Shrimps, Crabs, Snails: Threat – is aggressive – In the wild, this fish hunts at night for worms, crustaceans, insects and snails.
    • Plants: Safe

Sexual differences

Sexual differences are unknown.

Breeding / Reproduction

Captive breeding is possible but this probably won’t happen unless the fish are kept in a very large tank. In this case, that means 500 gallons or more. The pair will usually lay their eggs on floating plants and the male will aggressively guard them until they hatch in 6 or 7 days. The fry should be moved into a rearing tank and fed baby brine shrimp until they are large enough to take other foods..

  • Ease of Breeding: Difficult

Fish Diseases

The Clown Knife does not have scales which make it more prone to disease. Clown Knife are normally the first fish in a tank to show signs of ick and will twitch and rub around the tank. They respond well to most medication and normally heal quickly. NEVER use copper in a Clown Knife Fish tank.

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. Animal World is a great source for information on disease and treatments. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference.

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 Clown Knifefish 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.


Clown Knifefish are commonly available and moderately priced.



Featured Image Credit: suriyachan, Shutterstock