Clown knifefish care
Chitala ornata · Mekong and Chao Phraya basins of Southeast Asia: Cambodia, Laos, Thailand and Vietnam
Clown knifefish are silver, knife-shaped fish with a row of black, white-ringed spots near the tail.
- Tank size
- 250 US gal or larger
- Temperature
- 75 to 82 °F (24 to 28 °C)
- Group size
- Alone (one per tank)
- Temperament
- Semi-aggressive
- Adult size
- 39 in
- pH
- 6 to 7.5
- Hardness (GH)
- 4 to 15 dGH
- Lifespan
- 10 to 15 years
- Diet
- Carnivore
- Care level
- Demanding
Even a 210 gallon is too small
72½ × 24½ × 29⅝ in outsideHow to keep clown knifefish
Clown knifefish are silver, knife-shaped fish with a row of black, white-ringed spots near the tail. They are sold as 3-inch juveniles but can reach about 3 feet, so one adult needs a tank of 250 gallons or more with hiding places and dim light; it hunts at night and eats any fish it can swallow.
Diet: Carnivore: frozen shrimp and fish, earthworms, pellets for predatory fish. Fish food types compared · how often to feed.
Where they swim: Middle of the tank.
Clown knifefish tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
Fire eel
39 in · 180+ gal · 75–82 °F
Silver arowana
36 in · 250+ gal · 75–82 °F
Ornate bichir
24 in · 180+ gal · 75–82 °F
Black ghost knifefish
20 in · 125+ gal · 73–82 °F
Sailfin pleco
20 in · 150+ gal · 72–82 °F
Zig-zag eel
20 in · 55+ gal · 72–82 °F
Common pleco
18 in · 125+ gal · 72–82 °F
Royal pleco
17 in · 125+ gal · 72–82 °F
Keep apart
Neon tetra: Adult clown knifefish eat fish under about 4 in; neon tetras grow to 1.6 in.
Cardinal tetra: Adult clown knifefish eat fish under about 4 in; cardinal tetras grow to 1.2 in.
Black neon tetra: Adult clown knifefish eat fish under about 4 in; black neon tetras grow to 1.5 in.
Green neon tetra: Adult clown knifefish eat fish under about 4 in; green neon tetras grow to 1 in.
Ember tetra: Adult clown knifefish eat fish under about 4 in; ember tetras grow to 1.2 in.
Glowlight tetra: Adult clown knifefish eat fish under about 4 in; glowlight tetras grow to 1.5 in.
What a clown knifefish tank needs
A tank of 250 US gallons or more with a cover, and the equipment below.
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Fluval FX4
Rated by the maker for up to 250 US gal, which covers a 250 gallon clown knifefish tank without being built for a far bigger one.
Fluval FX6
Rated by the maker for up to 400 US gal, which covers a 250 gallon clown knifefish tank without being built for a far bigger one.
EHEIM thermocontrol 300
Clown knifefish need 75 to 82 °F; most homes run cooler, so a heater holds the temperature.
API Freshwater Master Test Kit
Tests ammonia, nitrite, nitrate and pH, the readings that matter most before and after adding clown knifefish.
Seachem Prime 100 mL
Removes chlorine and chloramine from tap water at every water change.
Fluval Edge Thermometer
Shows the water temperature at a glance, so you know it stays within 75 to 82 °F.
We don’t list fish food: any good brand of the foods under Diet will do. Plan the whole tank's equipment →
Common clown knifefish problems
- Tankmates small enough to swallow disappear at night.
- Two adults fight; keep one.
- Never release one: it has become invasive where it escaped outside Asia.
Test the water first whenever fish look unwell: see what your readings mean, then match the symptom. For disease, a vet who treats fish can diagnose it and advise treatment.
More to compare
Sources
Name, origin and adult size checked against Wikipedia: Chitala ornata. Temperature, pH, hardness, group size, lifespan and minimum tank size are common hobby guidance, not figures from that article. Ranges are the range the species tolerates; aim for the middle. Minimum tank sizes are for an adult group. Drawings are our own; photo credits follow.
Photo credits
Real photographs from Wikimedia Commons, resized and cropped to fit; each is used under the license named.
- Clown knifefish Parkourprincess, CC BY-SA 4.0, via Wikimedia Commons
- Fire eel Llandor, CC BY-SA 3.0, via Wikimedia Commons
- Silver arowana Qwertzy2, CC BY-SA 3.0, via Wikimedia Commons
- Ornate bichir Bloopityboop, CC BY-SA 4.0, via Wikimedia Commons
- Black ghost knifefish Vassil, CC0, via Wikimedia Commons
- Sailfin pleco AnatolyPm, CC BY-SA 4.0, via Wikimedia Commons
- Zig-zag eel Adolsomee, CC BY-SA 3.0, via Wikimedia Commons
- Common pleco Richwales, Public domain, via Wikimedia Commons
- Royal pleco Neale Monks at en.wikipedia, CC BY-SA 3.0, via Wikimedia Commons
- Neon tetra Holger Krisp, CC BY 3.0, via Wikimedia Commons
- Cardinal tetra CHUCAO, CC BY-SA 3.0, via Wikimedia Commons
- Black neon tetra Debivort, CC BY-SA 3.0, via Wikimedia Commons
- Green neon tetra Sascha Biedermann, CC BY-SA 2.5, via Wikimedia Commons
- Ember tetra Klaus Rudloff, CC BY-SA 4.0, via Wikimedia Commons
- Glowlight tetra gonzalovalenzuela; cropped by Kyknos, CC BY 2.0, via Wikimedia Commons
- Senegal bichir Zhyla at English Wikipedia, CC BY-SA 3.0, via Wikimedia Commons
- Elephantnose fish Jutta234, CC BY-SA 3.0, via Wikimedia Commons
- African butterflyfish Toniher, CC BY-SA 3.0, via Wikimedia Commons
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