Species profile
Three-lined Pencilfish
Nannostomus trifasciatus
Peaceful
Moderate care
80 L minimum aquarium
3.5–5 cm adult size
Top mid
Minimum group: 10
About this species
General notes for hobby use.
Peaceful shoaling pencilfish for soft, shaded water; aquarium size is driven by group behaviour rather than body length.
Water parameters
Suggested general range for long-term care.
Temperature
24–28 °C
pH
5.5–7
GH
1–10 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: 10
Tank zone
Top mid
Territory level
Low
Predation risk
Tiny fry
Bioload factor
0.45
Males display but serious aggression is unusual when a good-sized group has enough visual cover.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
Yes
Snail safe
Yes
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
Omnivore
Minimum aquarium volume
80 L
Minimum footprint
80 × 30 cm
Accepted scientific name
Nannostomus trifasciatus
Alternative names
Three-lined Pencilfish, Three-stripe Pencilfish
Native range
Amazon basin and Guiana Shield drainages.
Natural habitat
Slow forest water with vegetation, roots and leaf litter; use floating plants and subdued lighting.
Diet & feeding
Small dry foods plus frequent frozen/live micro-invertebrates.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Males are usually slimmer and more strongly coloured, females fuller-bodied.
Breeding
Egg-scatterer among fine vegetation; adults may eat eggs.