At a glance the quick version
Looks how to spot one
Elongated, weakly electric knifefish
A long, blade-shaped fish with no fin on its back. It moves by rippling one long fin along its belly, and has a short snout and a large mouth.2
Personality what they are like
Peaceful and rather shy with other species, but tends to argue with its own kind. Very small fish may be seen as food.3
Daily activity how busy a day looks
Nocturnal; it hunts at night and likes a dark daytime hideout.12
Grooming and care the hands-on bits
Water about 23-28 C, pH roughly 6.0-8.0 and soft to medium hardness. Strong filtration and regular water changes keep it at its best.13
Home where they are happiest
An adult needs a very large tank, at least 180 x 60 x 60 cm (about 650 litres), with tubes, roots or caves to hide in and a sandy bottom.31
Food basics what goes in the bowl
A carnivore: insect larvae, worms, earthworms, prawns and other live or frozen foods; many learn to accept dried foods too.132
Company who they like around
Best kept alone or as a group only in a very big tank. Good tankmates are peaceful fish over about 15 cm, such as angelfish or calm cichlids.3
The story where it all began
Carl Linnaeus described the species in 1766. In parts of South America local people traditionally linked the fish with spirits of the departed.12
Fun facts for the dinner table
- 1
Its electric organ lets it 'see' in dark or murky water and talk to other knifefish.2
- 2
It shifts its electric frequency to avoid clashing with neighbours, known as a jamming avoidance response.2
- 3
It can regrow a damaged tail, including part of the spinal cord.2
- 4
It has one of the lowest chromosome counts (24) known among bony fish.2
Recognised by the official bits
- IUCN Red List (via FishBase)
- Least Concern (assessed 2020).1
The care rhythm a typical week and year
A typical home-care rhythm for a Black Ghost Knifefish. A starting point, not a vet's advice.
- Feedingevery day
- Water changeAbout 30 to 50% of the waterevery week
- Water testevery week
- Filter rinseevery 2 weeks
Owner questions the things everyone asks
How often should I feed my Black Ghost Knifefish?
Feed your Black Ghost Knifefish once a day, ideally in the evening since it is nocturnal. Furry Diary's starting plan suggests daily feeding, and you can adjust the amount based on your fish's appetite and the food label.31 Pet Wiki plan
What does a Black Ghost Knifefish eat, and what should it never eat?
This carnivore enjoys live or frozen foods like insect larvae, worms, and prawns, and many will also accept dried foods. Never feed it anything that is not meant for fish, and avoid very small live prey that could be seen as food.312
How much space does a Black Ghost Knifefish need?
An adult needs a very large tank, at least 180 x 60 x 60 cm (about 650 litres), with tubes, roots, or caves to hide in and a sandy bottom. This gives it room to swim and feel secure.31
What temperature, light or water does a Black Ghost Knifefish need?
Keep the water at 23-28°C with a pH of 6.0-8.0 and soft to medium hardness. It is nocturnal, so provide dim lighting and a dark daytime hideout.132
How often should I clean a Black Ghost Knifefish's home?
Furry Diary's starting plan recommends a weekly water change of about 30 to 50% and a weekly water test, plus rinsing the filter every two weeks. Strong filtration and regular changes keep it at its best.1 Pet Wiki plan
Can a Black Ghost Knifefish live with others?
It is peaceful and shy with other species but may argue with its own kind, so it is best kept alone or in a group only in a very big tank. Good tankmates are peaceful fish over about 15 cm, like angelfish or calm cichlids.3
How long does a Black Ghost Knifefish live?
Lifespan varies depending on care and environment, so ask a good breeder or an exotic-pet vet for specific expectations. With proper care, they can live many years.
Can I handle a Black Ghost Knifefish?
No, handling is not recommended as it can stress the fish and damage its delicate body. It is best to observe it in its tank, especially at night when it is active.2
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
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Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.
- FishBase: Apteronotus albifrons fishbase.seused for size, origin, water parameters, IUCN, diet, history
- Wikipedia: Black ghost knifefish en.wikipedia.orgused for appearance, behaviour, diet, folklore, fun facts
- Seriously Fish: Apteronotus albifrons seriouslyfish.comused for tank size, water parameters, diet, compatibility, hand-feeding
Checked 2026-09-30. Text is written in our own words from these sources.