fish · Notopteridae
Clown knifefish
Chitala ornata
Wild range: Southeast Asia: Mekong basin in Laos, Thailand, Cambodia and Viet Nam, plus the Chao Phraya and Mae Klong basins of Thailand (FishBase). (Asia)
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At a glance: Clown knifefish care
Compiled reference information. Review the care notes and original sources below.
What temperature is listed for Clown knifefish?
The compiled profile lists 24.0–28.0 °C for Clown knifefish (Chitala ornata). Check the original sources below for context and differing recommendations.
What tank size is listed for Clown knifefish?
The profile lists a minimum tank volume of 200.0 US gallons (757.0 liters). Volume alone does not establish suitability; consider dimensions, group size and other inhabitants alongside the full care notes.
What pH is listed for Clown knifefish?
The compiled profile lists a pH of 6.0–7.5. Review the cited care sources alongside the other water parameters in this profile.
Natural habitat
The clown knifefish, or clown featherback, is a large Southeast Asian predator with a flattened, knife-shaped body and a row of dark, pale-ringed eyespots above the long anal fin. It is sold as a small juvenile but can reach about 1 m in the wild and often 50 cm or more in aquaria, so it is a specialist fish for very large tanks only. It is mostly active at night and eats any fish it can swallow. IUCN lists it as Least Concern.
Where they are found
Primary name Chitala ornata (Gray, 1831), valid in ITIS (TSN 649807) and in Catalog of Fishes and FishBase. Older synonyms: Notopterus ornatus, Notopterus ocellifer, Notopterus buchanani (FishBase via Atlarium). Often misidentified in the trade as Chitala chitala, which is rare in the hobby (Seriously Fish; Wikipedia); albino and leucistic line-bred forms are sold under the same name. Size: FishBase gives a maximum of 100 cm SL and 5 kg; aquarium specimens usually reach about 50 to 80 cm (ThinkFish; Tankora). Introduced and established outside its range, including southern Florida, the Philippines and Myanmar (Seriously Fish); never release it. IUCN: Least Concern (assessed 2010; FishBase).
Aquarium care
Keep it at 24–28°C, pH 6.0–7.5 and 2–15 dGH (FishBase; Atlarium; Seriously Fish; Aquarist; aquarium.guide). Treat 757 L / 200 gal as the absolute minimum for one adult (Aquarist; Aquarium Tank Mates); most guides ask for more, from 250 to 300 gal or about 950 L, with a tank at least 2 to 2.5 m long, because length matters more than height (aquarium.guide; Underground Aquarium; Tankora; Seriously Fish; ThinkFish). Use dim lighting or floating plants and give it a large refuge such as driftwood or a wide pipe (Seriously Fish; ThinkFish; Aquarium Tank Mates). It is a heavy-waste fish, so use a large mature filter, good oxygenation with some water movement, and large weekly water changes; Seriously Fish suggests 50–70% (Seriously Fish; Tankora). Use a heavy, tight lid because it can jump when startled (Tankora).
Feeding
A nocturnal predator that eats fish, crustaceans and insects in the wild (FishBase). Feed juveniles bloodworm, small earthworms and chopped prawn, and adults strips of fish, whole prawns, mussels and earthworms; many learn to take pellets, but don't make them the staple. Avoid mammal or bird meat such as beef heart, and skip feeder fish because of the disease risk (Seriously Fish; Aquarist; Tankora).
Compatibility
Keep one per tank, because it is intolerant of its own kind and of similar-shaped fish (Seriously Fish; ThinkFish; Aquarium Tank Mates). It will eat any fish small enough to swallow, so tankmates must be large, robust and peaceful, such as other big non-territorial oddballs in a very large tank (Aquarist; ThinkFish; Underground Aquarium). Not a community fish.
Breeding
Not reported in home aquaria. In the wild it spawns in flooded areas in the wet season, laying eggs on a hard surface, and the male guards the eggs (FishBase; Aquarist). ThinkFish reports both parents guarding, with care ending a few days after hatching.
Sources
Compiled from multiple independent care sheets — not copied from a single site.