Harlequin Rasbora
Trigonostigma heteromorpha
A hardy, copper-coloured shoaling fish with a black triangular patch, and one of the most reliable community fish available.
Ideal Conditions
- Temperature
- 22 – 27 °C
- pH range
- 5.5 – 7.5
- Hardness
- 2 – 12 dGH
- Adult size
- 3.5 – 4.5 cm
- Min. tank size
- 60 litres+
- Lifespan
- 4 – 6 years
- Diet
- Omnivore — small dry and frozen foods
- Water flow
- Low to moderate
- Preferred setup
- Planted tank with open swimming space and soft light
About the Harlequin Rasbora
The Harlequin Rasbora has been a community-tank staple for decades because it is peaceful, adaptable and looks best in exactly the conditions most planted tanks provide. It stays under 5 cm and tolerates a wide parameter range as long as conditions are stable.
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Is it right for your tank?
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Where Harlequin Rasbora comes from
Native range
South East Asia, Malay Peninsula
Countries / regions
Malaysia, Thailand, Singapore, Indonesia
Habitat
Peat swamp forest streams with soft, acidic, tannin-stained water and dense marginal vegetation.
Illustrative native range only, not an occurrence dataset.
Similar species
Lambchop Rasbora
Trigonostigma espei
Neon Tetra
Paracheirodon innesi
We’re adding more full species guides as the catalogue grows.
Compatible tank mates
Reviewed guidance based on this species' recorded traits.
- Great
Cardinal Tetra
Paracheirodon axelrodi
Matched size and temperament, and both use the same mid-water space without conflict.
- Great
Kuhli Loach
Pangio kuhlii
Occupies the bottom of the same soft, warm tank and ignores mid-water fish entirely.
- Great
Cherry Shrimp
Neocaridina davidi
Adult shrimp are too large to be eaten and the rasbora shows no interest in them.
- Not recommended
Pea Puffer
Carinotetraodon travancoricus
Pea Puffers nip fins persistently, and rasboras cannot escape them in a normal tank.
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