Order Osteoglossiformes
Suborder Notopteroidei
Family Notopteridae, Featherbacks ( Notopteridae )
Genus Chitala.
Sometimes it is difficult to distinguish juveniles of different knifefish species from one another. The growth rates of knifefishes are much higher than those of most other fishes, so when choosing tankmates, you need to plan with a large margin. In nature, knifefishes are crepuscular. In an aquarium, when kept in groups, they swim actively even during the day under bright light.
Identification: Genus Chitala — Chitala blanci, ornata.
— Blancs Featherback — Chitala blanci [Aubenton, 1965]. Synonym: Notopterus blanci. (Eng.: Blancs Featherback, Indochina Featherback, Royal Asian Knife Fish). Thailand, Laos, Cambodia, Mekong River. 90 cm. Humped, elongated, and laterally compressed body covered with small scales. Large mouth with numerous small teeth. The swim bladder is very large. At the bottom of the bladder, there is a chamber connected to the inner ear labyrinth, allowing the fish to use atmospheric air for breathing.
The dorsal fin is very small. The anal fin is long, running along the entire body from the pectoral fins and merging into the caudal fin. The fin is in constant motion, and through its wave-like movements and body undulations, the fish swims. Pectoral fins serve for maneuvering and as a rudder, allowing the fish to swim both forward and backward.
The body shape is similar to the better-known clown featherback Chitala ornata, but the coloration is silvery, with irregular dark oblique lines in the rear part that turn into rows of black spots in the front part of the body, extending onto the anal and caudal fins.
A characteristic feature of the Blancs featherback is a large black spot at the base of each pectoral fin, which appears in fry at a length of 6 cm and persists throughout life. With properly selected lighting, the fish shines like mercury or a mirror and looks extremely spectacular. The male is larger and slenderer than the female; the female has a rounded belly before spawning.
It is advisable to keep the Blancs featherback in a species aquarium with a volume of at least 300 liters, featuring various shelters made of rocks and driftwood, plant thickets along the edges, and open swimming space. Only young specimens are suitable for aquarium maintenance because they grow very rapidly and require more space with age. It is preferable to keep them singly or with large fishes (e.g., arowanas, bichirs, oscars, cichlasomas, large catfishes, giant gourami). The length of the knifefish’s neighbors should be 1.5-2 times the size of its mouth.
If there are two or more males in the aquarium, they can inflict serious injuries on each other during fights. A weak point of these fishes is the throat ligament. Its rupture can occur not only as a result of fights, but also due to injuries sustained when startled, when fishes crash into surrounding objects, as well as due to excessive greed when swallowing large pieces of food.
In nature, knifefishes are crepuscular. In an aquarium, when kept in groups, they swim actively even during the day under bright light. Lighting is subdued. It consumes live food: small fish, snails, crustaceans, worms. It should be trained to motionless food (pieces of meat, beef heart, squid, meat and fish fillets) gradually. Lifespan up to 10 years. pH 6.5-7.2; T 22-25°C.
— Ornate Clown Knife Fish, Clown Featherback — Chitala ornata [Gray, 1831]. Synonyms: Notopterus ornatus. (Eng.: Clown Featherback, Ornate Clown Knife Fish, Thousand Dollar Knife Fish). South and Southeast Asia, Mekong River basin. 70-80 cm, in aquariums usually 1.5-2 times smaller. This is a beautiful, contrastingly colored fish. They have an unusual body shape, wave-like movements of their body and fins, and a bright silvery sheen on their flanks adorned with distinct ocellated spots.
The main body color is grayish-blue, with 6-15 ocellated spots surrounded by a white ring in the rear part along the anal fin. The anal fin is brown with a patterned design of interlacing light lines. The most beautiful pattern is found in juveniles; the more interlacings, the more “eyes” the adult fish will have.
The fins are dark gray. The anal fin is long, running along the entire body from the pectoral fins and merging into the caudal fin. The fin is in constant motion, and through its wave-like movements and body undulations, the fish swims.
Usually, juveniles 8-12 cm long are offered for sale, having a quite docile temperament and looking just as attractive as adult specimens. They behave relatively calmly, exploring the territory and gaining strength. Only after some time does the aquarist realize what a mistake they made. The fact is that featherbacks in general, and clown featherbacks in particular, are exceptionally aggressive.
They do not tolerate the presence of not only fishes of other species in their immediate vicinity, but also their own kin. While juveniles can still be kept in the company of commensurately large cichlids, arowanas, and other knifefishes, selecting suitable neighbors for adult specimens is extremely difficult. Generally, featherbacks must be kept singly.
Being active predators with an excellent appetite, clown featherbacks are always ready to greedily pounce on anything that moves and comes within their reach. To curb the aggression of young specimens, they should be kept in spacious (from 500 liters) aquariums densely planted with aquatic vegetation and equipped with plenty of shelters. They prefer soft, neutral water with T 24-26°C, but also do well at dH 14-18°.
Filtration, aeration, and weekly water changes of up to 30% are required. They readily eat any live food (small fish, tadpoles, worms), eventually getting used to motionless food (meat, beef heart, liver, etc.), including granulated and freeze-dried foods for pond and large aquarium fishes. Sexual maturity is reached at the age of 3 years. They live up to 10 years.
Chitala chitala, Indian featherback.
Papyrocranus afer, Xenomystus nigri, African knifefish. 
