Poor pairing in a typical community
An adult Oscar can view this much smaller species as prey.
Practical response: Choose large, robust tankmates only in a suitably large Oscar system.
Cardinal Tetra
- Adult size
- 5 cm / 2 in
- Tank reference
- 60+ L / 15.9+ US gal
- Group
- 8+
- Zone
- mid
- Temperature
- 23–29°C / 73.4–84.2°F
Oscar
- Adult size
- 35 cm / 13.8 in
- Tank reference
- 280+ L / 74+ US gal
- Group
- 1+
- Zone
- mid
- Temperature
- 23–28°C / 73.4–82.4°F
Water parameter overlap
Behavior and space
A warm-water schooling tetra that prefers stable, softer water and a sizeable group. A large predatory cichlid with heavy waste production and substantial space requirements.
A compatibility answer should also consider the actual tank dimensions, number of each fish, filtration, planting and other occupants. Two species can be reasonable together in a long, structured aquarium yet become a poor pairing when compressed into a small footprint.
Common questions
Can Cardinal Tetra live with Oscar?
The StockingLab verdict is avoid: An adult Oscar can view this much smaller species as prey.
Do their temperatures overlap?
23–28°C / 73.4–82.4°F shared range.
Should I trust compatibility calculators completely?
No. Individual behavior, sex ratios, breeding condition, aquascape and tank size can change the outcome. Use the result to identify risks, then verify care requirements before purchase.