Possible, but with meaningful cautions
Their temperature overlap is narrow, leaving little room for seasonal or measurement variation.
Practical response: Target the middle of the shared temperature range and monitor stability.
Harlequin Rasbora
- Adult size
- 4.5 cm / 1.8 in
- Tank reference
- 50+ L / 13.2+ US gal
- Group
- 8+
- Zone
- mid
- Temperature
- 22–28°C / 71.6–82.4°F
Discus
- Adult size
- 16 cm / 6.3 in
- Tank reference
- 250+ L / 66+ US gal
- Group
- 5+
- Zone
- mid
- Temperature
- 28–31°C / 82.4–87.8°F
Water parameter overlap
Behavior and space
A reliable community shoaler that appreciates plants around open swimming space. Large warm-water cichlids usually kept in groups; stable water and low-stress tankmates are essential.
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 Harlequin Rasbora live with Discus?
The StockingLab verdict is caution: Their temperature overlap is narrow, leaving little room for seasonal or measurement variation.
Do their temperatures overlap?
28–28°C / 82.4–82.4°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.