Harlequin Rasbora
Trigonostigma heteromorpha
The harlequin rasbora (Trigonostigma heteromorpha) is a small, peaceful schooling fish recognizable by its black triangular patch on the rear of the body. Highly gregarious, it must live in groups of at least eight to ten individuals to express its natural behavior. Its adult size is 4 to 5 cm.
Parameters
- Water type
- Freshwater
- Min volume
- 60 L
- Temperature
- 22–27 °C
- pH
- 6–7
- Hardness (GH)
- 2–12 °GH
- Adult size
- 5 cm
- Lifespan
- 5 years
- Diet
- Omnivore
- Temperament
- Paisible
- Difficulty
- Débutant
Environment
A minimum 60-liter tank, densely planted with open swimming areas and subdued lighting, suits it perfectly. It prefers soft and slightly acidic water (pH 6.0 to 7.0) between 22 and 27 °C, ideally filtered through peat or enhanced with catappa leaves. A dark substrate brings out its colors.
Feeding
Omnivorous and undemanding, it accepts fine flakes, micro-pellets, and small live or frozen prey (artemia nauplii, daphnia, bloodworms). Distribute small amounts several times a day. Dietary variety enhances the intensity of its colors.
Health & common diseases
The Harlequin Rasbora is a hardy fish but can be susceptible to ichthyophthirius (white spot disease) in case of stress or temperature drop. Fin rot can occur in poor water quality. Watch for white spots, frayed fins, or lethargic behavior. Good water quality (regular water changes of 20-30% weekly), stable temperature (24-26°C), and a varied diet prevent most diseases.
Tips & tankmates
Kept in a tight school, it becomes more active and colorful; in too small numbers it remains timid. It is an excellent companion for a peaceful community tank with other small, peaceful species. Avoid boisterous or predatory tankmates.
Sources
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Information provided for guidance only; it may vary between individuals and conditions. If in doubt about an animal's health, consult a vet.