The clown knifefish (Chitala ornata) is one of the most impressive freshwater fish in the aquarium world, with its unique knife-shaped body and predatory character that glides silently through the darkness of night. This exotic species from the great rivers of Southeast Asia captures the attention of aquarium enthusiasts with both its physical appearance and interesting behaviors.
Belonging to the Notopteridae family, the clown knifefish is also known as “Clown Featherback” or “Spotted Knifefish.” Named “clown” due to the eye-shaped spots on its body, this fish adds a different atmosphere to aquariums with its elegant swimming style and mysterious nature.
Clown Knifefish Characteristics
The clown knifefish has a laterally compressed, elongated knife-shaped body. This unique body structure gives the fish the ability to move both forward and backward. The anal fin merges with the caudal fin, creating an undulating structure that extends along the bottom of the body.
While striped patterns are seen in juveniles, these stripes are replaced by 5-10 black spots within white rings in adult fish. These eye-shaped spots are the most distinctive feature that gives the fish its “clown” name. The base body color is silvery-gray, and the fins are slightly darker gray.
Size and Lifespan
The clown knifefish is a large species that can reach 100 cm (1 meter) in length and 5 kg in weight in its natural environment. In aquarium settings, they typically stay between 45-60 cm. With proper care conditions, they can live 10-15 years or even longer.
Unique Features
One of the most striking features of the clown knifefish is its ability to breathe air. Thanks to its modified swim bladder, it can survive even in waters with low oxygen levels. This feature is a result of adaptation to stagnant waters in their natural habitat.
Another interesting feature is their strong sense of smell. They can easily find their food using this developed sensory organ while hunting in the dark.
Clown Knifefish Behavior
Clown knifefish are nocturnal animals. During daylight hours, they generally prefer to hide in dark corners of the aquarium, among rocks, or under plants. They become active and go out hunting as evening darkness begins to fall.
Hunting Behavior
They are extremely effective predators both in their natural environment and in aquariums. They view any creature that can fit in their mouths as prey. They wait in ambush and catch their prey with a quick strike when the opportunity arises. For this reason, they should not be kept with small fish.
Social Behavior
While juveniles can live in small groups, adult clown knifefish display a highly territorial character and prefer to live alone. Adult individuals may show aggressive behavior when kept in the same tank.
Interestingly, they can recognize their owners over time and become more interactive during feeding times.
Clown Knifefish Habitat
The clown knifefish is native to the Mekong, Chao Phraya, and Meklong river basins of Southeast Asia. They naturally live in the freshwater ecosystems of Thailand, Laos, Cambodia, and Vietnam.
Their natural habitats are slow-flowing rivers, lakes, swamps, and floodplains. They prefer to live in shallow waters where vegetation is dense and logs and rocks are abundant. These structures are used both as hiding places and nesting areas during the breeding season.
Aquarium Requirements
Due to the large size of the clown knifefish, a spacious aquarium is required:
Tank Size:
Minimum 200 liters for juveniles, minimum 500-750 liters for adults, ideally 1000+ liters is recommended.
Water Parameters:
Temperature: 24-29°C (ideal: 26-27°C)
pH: 5.5-7.0 (ideal: 6.0-6.5)
Hardness: 2-10 dGH
Tank Setup:
Dim lighting (strong light causes stress), plenty of hiding spots (caves, pipes, logs), floating plants (to filter light), open swimming areas, and a tightly closing lid (they are good jumpers) are required.
Clown Knifefish Feeding
Clown knifefish are completely carnivorous. In their natural environment, they feed on small fish, crustaceans, insects, and worms.
Feeding in Aquarium
Preferred foods: Live feeder fish, fresh shrimp, worms (bloodworms, earthworms), mussel and squid pieces, frozen fish slices.
Feeding Tips: Feed them in the evening hours as they are nocturnal. Give food after the lights are turned off. They have difficulty adapting to dry food, be patient. Avoid overfeeding (they are prone to obesity). Feeding 4-5 times a week is sufficient.
Juveniles are fed with bloodworms and finely chopped shrimp, while adults can be fed with whole shrimp, fish slices, and large worms.
Clown Knifefish Breeding
Breeding clown knifefish in aquarium conditions is quite rare and difficult. However, their breeding behavior in the natural environment is known.
The breeding season usually occurs during the rainy season (March to July). The male fish prepares a nest from branches and leaves. The female deposits her eggs on a hard surface or underwater plants. The male takes on the duty of protecting the eggs and fry.
The eggs hatch within 6-7 days. Fry care is done by the male; he fans the eggs and keeps other fish away.
Tank Mates
Due to the large size and predatory nature of the clown knifefish, choosing compatible tank mates is critically important.
Compatible Species: Arowana, large cichlids (Oscar, Dovii), large catfish (Pleco, Pimelodidae), Bichir species, giant gourami, other knifefish of the same size.
Species to Avoid: Small community fish (seen as prey), aggressive and territorial small fish, slow-moving small species.
General rule: Any fish that can fit in their mouths is considered potential prey.
Clown Knifefish Diseases
Although they are generally hardy fish, some common problems can be seen:
Ich (White Spot Disease): White spots may form when under stress or when water quality drops. It is treated by slowly increasing the water temperature and with appropriate medications.
Fin Rot: Fin deterioration occurs as a result of poor water quality. It can be prevented with regular water changes and good filtration.
Feeding Problems: They may have difficulty transitioning to dry food. They can be accustomed with patience and by trying various foods.
Prevention: Regular water changes (20-30% weekly), good filtration system, avoiding stress factors, and selecting appropriate tank mates are recommended.
Frequently Asked Questions
How big do clown knifefish get?
They can grow to 45-60 cm in aquariums and up to 100 cm in nature. A large aquarium is essential.
How long do clown knifefish live?
With proper care conditions, they can live 10-15 years or even longer.
Are clown knifefish aggressive?
They show predatory behavior towards small fish. They can be territorial towards their own species in adulthood. They are compatible with large, calm fish.
What is the ideal aquarium size for clown knifefish?
A minimum of 500 liters for an adult, ideally 750-1000 liters is recommended.
Do clown knifefish eat dry food?
They naturally prefer live and fresh foods. It may be difficult to accustom them to dry food, but it is not impossible.
Why are clown knifefish not visible during the day?
They are nocturnal species. They prefer to rest in hiding places during the day.
Can clown knifefish live with other fish?
Yes, but only with large and calm species. They see small fish as prey.
Why do clown knifefish jump?
They are good jumpers, especially when under stress. The aquarium lid must be kept closed at all times.
Clown Knifefish at Emaar Aquarium
Emaar Aquarium and Underwater Zoo brings the mysterious world of the clown knifefish to its visitors. Located in the Waterfalls and Rivers thematic area, this exotic species is displayed in a special tank reminiscent of its natural habitat.
At our aquarium, you can find the opportunity to closely observe the elegant swimming, unique body structures, and characteristic eye-shaped spots of clown knifefish. Watching the hunting behaviors of these night predators during feeding programs held especially in the evening hours offers a truly impressive experience.
Our clown knifefish, carefully cared for by our expert keepers in an environment closest to the natural conditions of Southeast Asian rivers, give our visitors the opportunity to learn about this rare species. Visit Emaar Aquarium to discover this fascinating member of freshwater ecosystems.
