Species profile
Rainbow Emperor Tetra
Nematobrycon lacortei
Peaceful
Moderate care
80 L minimum aquarium
3.5–4.5 cm adult size
Midwater
Minimum group: 8
About this species
General notes for hobby use.
Soft-water emperor tetra; adult males display and spar, so provide visual breaks and enough floor/plant structure for multiple display areas.
Water parameters
Suggested general range for long-term care.
Temperature
23–27 °C
pH
5.5–7.2
GH
Up to 12 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: 8
Tank zone
Midwater
Territory level
Low
Predation risk
Tiny fry
Bioload factor
0.65
Generally peaceful; male rivalry is display-based rather than serious fighting when the aquarium is spacious.
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 × 35 cm
Accepted scientific name
Nematobrycon lacortei
Alternative names
Rainbow Emperor Tetra, Lacorte's Tetra
Native range
Colombia, particularly Pacific-drainage forest streams.
Natural habitat
Shaded forest tributaries with soft, often acidic water and abundant cover.
Diet & feeding
Small invertebrates form much of the natural diet; use quality prepared foods plus frozen/live supplements.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Males show stronger colour and extended fin rays; females are fuller and less ornate.
Breeding
Egg scatterer with no parental care; soft acidic spawning water improves success.