Species profile
Cardinal Tetra
Paracheirodon axelrodi
Peaceful
Moderate care
70 L minimum aquarium
3–4 cm adult size
Midwater
Minimum group: 8
About this species
General notes for hobby use.
Soft-water shoaling tetra that rewards stable, clean conditions and a sizeable group. Many in the trade are wild caught, so acclimation to very different water should be gradual.
Water parameters
Suggested general range for long-term care.
Temperature
23–27 °C
pH
4–7
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
None
Predation risk
Tiny fry
Bioload factor
0.5
Peaceful and non-territorial. Keep with similarly calm fish and avoid predators or boisterous feeders; a larger shoal gives more natural behaviour.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Yes
Shrimp safe
No / caution
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
70 L
Minimum footprint
60 × 30 cm
Accepted scientific name
Paracheirodon axelrodi
Alternative names
Cardinal
Native range
Upper Orinoco and Rio Negro drainage systems of Venezuela, Colombia and Brazil.
Natural habitat
Associated with acidic blackwater/clearwater tributaries and flooded forest environments rich in leaf litter and woody cover.
Diet & feeding
Tiny invertebrates form an important natural food component. Feed small complete foods plus daphnia, Artemia and similar frozen/live foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Mature females are usually fuller-bodied; males tend to remain slimmer. External differences are subtle.
Breeding
Egg scatterer requiring very soft acidic water for reliable breeding. Adults do not provide parental care and may eat eggs.