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.
Rummy-nose Tetra
- Adult size
- 5 cm / 2 in
- Tank reference
- 75+ L / 19.8+ US gal
- Group
- 8+
- Zone
- mid
- Temperature
- 24–28°C / 75.2–82.4°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
An active, tight-schooling tetra that rewards stable water quality and generous swimming length. 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 Rummy-nose 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.