Home / Fishes / Arowanas and elephantfish / Clown featherback
No federal permit to keepClown featherback
Chitala ornata
Fishes › Arowanas and elephantfish (Osteoglossiformes) › Notopteridae (Asian and African knifefish)
The clown featherback (Chitala ornata), also known as the clown knifefish and spotted knifefish, is a nocturnal species of tropical fish with a long, knife-like body.
Care at a glance
Species-specific aquarium care
- Tank: An adult reaches about 39.4 in (100 cm). That needs a pond or public-aquarium-scale system, far beyond a home aquarium.
- Water: Freshwater.
- Temperature: 75–82°F (range recorded for this species).
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
- Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–82 °F, pH 6–8, 2–15 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Prefers dim lighting and access to refuges in the form of driftwood, large rocks or lengths of plastic piping.”
- Diet: “An obligate, typically nocturnal, predator feeding on smaller fishes, crustaceans and other invertebrates in nature but in most cases adapting well to dead alternatives in captivity.”
- Tankmates: “Relatively peaceful with fishes too large to be considered prey but can be territorial with conspecifics and other similarly-shaped species, especially if space is at a premium.”
- Breeding: “Unreported in captivity but in nature male individuals contruct nests from branches and leaves and remains to guard the eggs and fry post-spawning, which takes place in areas of flooded forest during the wet season.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Asian and African knifefishes
Applies to most species in this group. Habitat: Notopterids inhabit African and Asian freshwaters, including still, vegetated waters, rivers, lakes and floodplains, with Chitala ornata entering flooded forest to spawn. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For Xenomystus nigri, the cited lifetime aquarium is approximately 120 x 45 x 38 cm, about 205 litres, for one fish.
- For Chitala ornata, plan a public installation or exceptionally large specialist aquarium: adults reach about 100 cm standard length.
- Provide dim light and refuges made from smooth wood, rocks or appropriately sized pipes; planted cover and soft sand particularly suit X. nigri.
- For large Chitala, install mature filtration, oxygenated water and substantial regular water changes; the C. ornata reference specifies 50–70% weekly.
- Preserve access to the water surface for atmospheric breathing.
Diet
- Bloodworms and earthworms, with smaller portions for juveniles.
- Prawns or shrimp and chopped mussels.
- Marine fish flesh for larger Chitala.
- Carnivore pellets if accepted, with varied meaty foods rather than pellets alone for C. ornata.
Social life
- Keep fish too large to swallow as any companions; provide separation for territorial adults. X. nigri becomes less tolerant of its own species with maturity, and Notopterus notopterus is more aggressive.
Health watch
- Nutritional organ damage from unsuitable mammalian or avian meat in Chitala.
- Ammonia toxicity under inadequate filtration.
- White spot disease, a general freshwater aquarium risk.
Understanding the animal
About this animal
About this animal
This knifefish is native to freshwater habitats in Cambodia, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, but it has also been introduced to regions outside its native range. It is one of the world's most invasive species.
Quoted from the Wikipedia article “Clown featherback” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater, in rivers and streams, lakes. Inhabits flowing waters of large and medium-sized rivers. |
| Water it lives in | Freshwater, 75–82 °F (24–28 °C). |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
| Behavior to plan for | Breeding: paternal parental care. |
What this means for care
- Keep water within its wild range, 75–82 °F.
- Parents guard eggs or young, so expect territorial behavior when breeding.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 94°F (up to 97°F in the hottest sampled areas) |
| Cool-season lows | about 65°F (down to 55°F in the coldest sampled areas) |
| Average temperature | 75–82°F across sampled records |
| Relative humidity | 71–77% on average (driest month about 64%) |
| Rainfall | about 1627 mm a year, with strong wet and dry seasons |
Measured at 43 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | The clown featherback (Chitala ornata), also known as the clown knifefish and spotted knifefish, is a nocturnal species of tropical fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, China, Hong Kong, Laos, Macau, Thailand, and Vietnam, but it has also been introduced to regions outside its native range. It is one of the world's most invasive species. It is often seen in aquaculture and the aquarium trade, where it is frequently confused with Chitala chitala; the latter species is very rare in the aquarium trade. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Behavior | These fish are primarily carnivorous, allowing them to widen their food spectrum in response to environmental changes In their native habitat, they have very few natural predators; they are at the top of the food chain in newly inhabited waters, often preying on smaller fish, crustaceans, and insects. Juveniles tend to hunt near vegetation and congregate for protection, becoming independent as they mature. — Wikipedia (community-edited) |
| Appearance and size | Chitala species have distinct physical features that set them apart from other fishes. A grey-silver, laterally compressed body and long anal fin that extends to the caudal fin in the composition presents a knife appearance. A row of 6-10 oscillated black spots with white borders above the anal fin base, and lack of faint lines on their back differentiates C. ornata from the rest of the genus. — Wikipedia (community-edited) |
| Biology | Obligate air-breathing; Adults inhabit flowing waters of large and medium-sized rivers. Within the Mekong mainstream, they occur in pools (, 36667 ). They feed on surface-feeding fishes, crustaceans and insects, with a crepuscular or nocturnal activity pattern. — FishBase |
| History and naming | The clown knifefish belongs to the family Notopteridae, which can be found in Africa and Asia (including India). Notopterids can be characterized by their laterally compressed bodies accompanied by an elongated anal fin. The origin of notopterids can be traced back to the Early Cretaceous when the African and Asian clades split, redistributing the genus between both regions. — Wikipedia (community-edited) |
| Conservation | The International Union for Conservation of Nature has listed the clown knifefish as "least concern", due to their wide native range and ability to withstand diverse, unfavorable conditions. Although the species has a large presence in Southeast Asian aquaculture, it is widely known as an invasive species to regions primarily in Asia and the United States. — Wikipedia (community-edited) |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Typical adult weight
Average adult body mass in each database (FishBase gives the maximum recorded weight).
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
pH
Water hardness
Veterinary & husbandry research
Veterinary & husbandry research
- The effects of elevated environmental CO(2) on nitrite uptake in the air-breathing clown knifefish, Chitala ornata Gam LTH et al., Aquatic toxicology (Amsterdam, Netherlands) 2018
Peer-reviewed papers that mention this species alongside captivity, zoos, veterinary care or aquaculture. Some cover several species or mention it only in passing, so check the abstract. 170
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Xenomystus nigri Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Chitala ornata Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- PubMed (U.S. National Library of Medicine) Peer-reviewed researchIndex of peer-reviewed veterinary, zoo and husbandry research.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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