Poor pairing in a typical community
Their preferred pH ranges do not overlap.
Practical response: Choose species suited to the same source water rather than chasing pH chemically.
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
Molly
- Adult size
- 9 cm / 3.5 in
- Tank reference
- 90+ L / 23.8+ US gal
- Group
- 4+
- Zone
- mid
- Temperature
- 24–28°C / 75.2–82.4°F
Water parameter overlap
Behavior and space
A warm-water schooling tetra that prefers stable, softer water and a sizeable group. A comparatively large, high-output livebearer needing space, hard water and robust filtration.
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 Molly?
The StockingLab verdict is avoid: Their preferred pH ranges do not overlap.
Do their temperatures overlap?
24–28°C / 75.2–82.4°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.