Species profile
Glass Knifefish
Eigenmannia virescens
Peaceful
Hard care
700 L minimum aquarium
25–45 cm adult size
Bottom–mid
Minimum group: 6
About this species
General notes for hobby use.
Gregarious despite its size; groups of six or more require very large quarters.
Water parameters
Suggested general range for long-term care.
Temperature
23–28 °C
pH
6–7
GH
2–15 dGH
KH
Not yet documented
Flow preference
Low–moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 6
Tank zone
Bottom–mid
Territory level
Low
Predation risk
Small fish
Bioload factor
3
Shy, nocturnal and peaceful with suitable tankmates; avoid small fish/invertebrates and other knifefish.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
No / caution
Snail safe
No / caution
Cave breeder
No
Digs substrate
No
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Carnivore
Minimum aquarium volume
700 L
Minimum footprint
180 × 75 cm
Accepted scientific name
Eigenmannia virescens
Alternative names
Green Knifefish
Native range
Broad South American distribution from Magdalena/Orinoco/Amazon systems south toward the La Plata basin.
Natural habitat
Deep quiet waters and floodplain habitats with plant debris. Use a 180 × 75 cm-class dim aquarium with sand, large dark refuges and gentle flow.
Diet & feeding
Micro-predator; varied frozen/live invertebrates and quality sinking carnivore foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Males become much larger than females, sometimes nearly twice their length.
Breeding
Courtship involves electrical signalling; adhesive eggs are reported to be deposited on vegetation.