Species profile
African Brown Knife Fish
Xenomystus nigri
Semi aggressive
Moderate care
300 L minimum aquarium
20–30 cm adult size
Mid bottom
Can be kept singly
About this species
General notes for hobby use.
Provide dark retreats and ensure food reaches this nocturnal fish. A tight lid is essential.
Water parameters
Suggested general range for long-term care.
Temperature
23–28 °C
pH
6–7.5
GH
2–15 dGH
KH
Not yet documented
Flow preference
Low
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Can be kept singly
Tank zone
Mid bottom
Territory level
Moderate
Predation risk
Small fish
Bioload factor
3
Nocturnal knifefish that shelters by day. Can coexist with sturdy fish too large to eat, but small fish and shrimp are vulnerable.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
No / caution
Snail safe
Yes
Cave breeder
Yes
Digs substrate
No
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
10–15 years
Diet type
Carnivore
Minimum aquarium volume
300 L
Minimum footprint
150 × 50 cm
Accepted scientific name
Xenomystus nigri
Alternative names
African Knifefish, Brown Knifefish
Native range
West and Central African river systems.
Natural habitat
Slow rivers, backwaters and vegetated margins with roots, caves and subdued lighting.
Diet & feeding
Aquatic insects, crustaceans and small fish; feed sinking/floating meaty foods after lights dim, including frozen invertebrates.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Sexes are not reliably distinguishable by routine external appearance.
Breeding
Captive spawning is rare. Eggs are deposited in sheltered crevices/caves and male brood guarding has been reported.