Apistogramma and Harlequin Rasbora: Can They Live Together?
Side-by-side comparison
| Factor | Apistogramma | Harlequin Rasbora | Assessment |
|---|---|---|---|
| Water temperature | 75–83°F | 73–82°F | Overlap 75–82°F |
| pH | 5.5–7 | 6–7.5 | Overlap 6–7 |
| Hardness | 2–12 dGH | 2–15 dGH | Overlap 2–12 dGH |
| Adult size | 3.0″ | 1.8″ | Similar |
| Temperament | Semi | Peaceful | Watch territory |
| Swim level | Bottom | Mid | Different zones |
| Minimum tank | 20 gal | 10 gal | Together: 26 gal+ |
Shared water parameters
- Temperature both tolerate: 75–82°F
- pH both tolerate: 6–7
- Hardness both tolerate: 2–12 dGH
- Recommended combined tank: 26 gallons or larger
Risks and things to watch
Spawning aggression
Semi-aggressive species are usually calm until they pair off. Expect a territory to be claimed and defended around caves or flat surfaces.
Group requirements
Compatibility is not only about the two species getting along — each still needs its own social setup met inside the same tank.
- Apistogramma — no group requirement; single specimens are fine.
- Harlequin Rasbora — minimum group of 6. Budget tank space for the whole shoal, not one fish.
Frequently asked questions
Can apistogramma and harlequin rasbora live together?
Possible, with conditions. Apistogramma and Harlequin Rasbora can work, but this is a conditional yes rather than easy one. Read the risk section below before buying — the pairing usually fails for one specific reason, not because of general incompatibility. Plan on 26 gallons minimum.
What size tank do apistogramma and harlequin rasbora need together?
Plan for at least 26 gallons. Apistogramma alone needs 20 gallons and Harlequin Rasbora needs 10, but combined stocking needs headroom for filtration and swimming space, not just volume.
What temperature suits both species?
Both are comfortable between 75 and 82°F. Set the heater to the middle of that window and keep it stable.
What pH works for both?
Aim for pH 6–7, which sits inside both species' comfortable range.
Will apistogramma eat harlequin rasbora?
Unlikely. At 3.0″ versus 1.8″ the size gap is not large enough for predation, though fry and juveniles are never safe in a community tank.
How should the tank be arranged?
Use plants, wood and rock to break sight lines, keep open swimming space along the front, and add the more territorial species last so it cannot claim the whole tank before the other settles in.
Explore further
Assessment generated from our compatibility methodology: parameter overlap, adult size ratio, temperament and swimming zone. Reviewed by Marcus Rivera.