Best for
Aquariums where its role fits: schooling midwater.
C
Fish · Freshwater
Cardinal tetra
Paracheirodon axelrodi
The cardinal tetra is an Amazonian schooling tetra that looks best in large groups and warm, soft, stable water. Its intense color depends on calm surroundings, dark background and good water quality.
It is excellent for mature Amazonian tanks and can live with discus when individuals are adult, volume is suitable and large predators are absent.
Difficulty
Intermediate
Aggression
5/10
Schooling
Yes
Size
5.00 cm
Minimum volume
80 L
Temperature
24.0-28.0 ºC
Zone
Midwater
Lifespan
5 years
Quick profile scan
fish
Territoriality
Low
Aggression
5/10
Activity
Moderate
Thermal sensitivity
High
Bioload
Low
Speed
Moderate
Predation risk
None
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Check whether this species fits your aquarium
Analyze volume, parameters, behavior and relationships with other species.
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Quick verdict
A practical summary to quickly decide whether it fits your aquarium.
Avoid
Mixes marked as high risk or not recommended in manual relationships.
Compatible with
Has positive or conditional references with species such as Discus.
Typical risk
Stability depends on temperature, group size, and real compatibility.
Aquarium zone
Where it lives best
Surface
Midwater
primary
Bottom
Quick compatibility
Community signals
Shrimp
Compatible
Snails
Compatible
Slow fish
Compatible
Aggressive fish
Conditional
Small fish
Compatible
Large fish
Compatible
Delicate plants
Conditional
Buying decision
Before buying Cardinal tetra
Review these points before adding it to your aquarium. They are practical notes based on its profile, ecological data, and known relationships.
L
Adult volume
Make sure your aquarium is above 80 L before buying it.
G
Minimum group
Do not keep it alone if it needs a group; plan space for the right number of individuals.
C
Stable temperature
Avoid keeping it at the edges of its temperature range for long periods.
Parameters
Water conditions
pH
5.5 - 7.0
GH
1 - 10
KH
0 - 5
Temperature
24.0 - 28.0 ºC
Growth and behavior
Juvenile to adult
Juvenile
As a juvenile it feels safer in a group and usually uses the midwater area with coordinated movement. An insufficient group can increase stress and erratic behavior.
Shift
The transition to adulthood usually brings more stable behavior when group size, space and parameters are suitable.
Adult
As an adult it keeps a strong social pattern and is more stable in adequate groups. In balanced communities it usually occupies the midwater area without causing major conflict.
Ecological profile
Role and biological pressure
Schooling Midwater
Community Fish
Small
Low
Moderate
None
Profile: midwater schooling species, with low bioload and primary use of the midwater area. It should be kept in a group to show stable behavior and reduce stress. Temperature stability matters; avoid long-term maintenance at the edges of its range.
Ecological radar
profile
Territoriality
24%
Aggression
50%
Activity
52%
Thermal sensitivity
78%
Bioload
24%
Common mistakes
What to avoid
Keeping it in tanks below the recommended adult volume.
Keeping too few individuals for a social species.
Keeping temperature at the edges of the range for long periods.
Relations
Compatible with
✓
D
Discus
Compatible
Main risk: Water parameters
Low risk
Symphysodon aequifasciatus + Paracheirodon axelrodi: cohabitation is usually viable if volume, parameters, groups and adult behavior are respected.
Angelfish
Conditional
Main risk: Predation
Review conditions
Pterophyllum scalare + Paracheirodon axelrodi: there is a predation risk due to size difference, mouth capacity or feeding behavior.
Guppy
Conditional
Main risk: Thermal stress
Review conditions
Poecilia Reticulata + Paracheirodon axelrodi: water parameters are not fully compatible or only overlap within a limited range.
Siamese Fighting Fish
Conditional
Main risk: Territorial behavior
Review conditions
Betta splendens + Paracheirodon axelrodi: territoriality, dominance or competition for calm areas of the aquarium may occur.
T
Tiger barb
Conditional
Main risk: Fin nipping
Review conditions
Puntigrus tetrazona + Paracheirodon axelrodi: there is a risk of fin nipping, harassment or stress in slow, nervous or long-finned species.
Relations
Avoid keeping with
!
Oscar
Not recommended
Main risk: Predation
Not recommended
Astronotus ocellatus + Paracheirodon axelrodi: there is a predation risk due to size difference, mouth capacity or feeding behavior.
G
Goldfish
Not recommended
Main risk: Thermal stress
Not recommended
Carassius auratus + Paracheirodon axelrodi: this combines coldwater or temperate species with tropical species that need different temperatures.
Essential care
Keep large groups, moderate lighting and shaded areas. Avoid newly set up tanks, very hard water and fast or aggressive tankmates. Acclimation should be careful.
Daily time
10 min
Related biomes
Breeding
Breeding is difficult in community aquariums. It requires very soft water, low light and careful handling of sensitive eggs. It is usually kept as an ornamental schooling species rather than a casual breeding project.
Oviparous
Moderate
Machos algo más esbeltos; hembras más robustas
Alerts and health
- Acuario maduro
- Grupo grande
- Agua estable
Common issues
Ich
Parásitos externos
Expert notes
Interesting details
01
Es una especie muy popular en acuariofilia
02
Se aprecia más cuando se mantiene correctamente
Editorial confidence
Last review: June 2026
Content based on parameters, ecological profiles and manual relationships.
Profile data
Ecological profile
Manual relationships
General aquarium observation
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