Overview
The Harlequin Rasbora (Trigonostigma heteromorpha) is a beginner freshwater species known for its orange-pink, black triangle coloration. Classic schooling fish. Mid.
Origin & Appearance
Origin: Southeast Asia.
Colors: Orange-Pink, Black triangle.
Body Shape: Fusiform (torpedo/streamlined). Typical adult dimensions: 5.0 x 0.9 x 1.5.
Sexual Dimorphism: Subtle; males have straighter body wedge shape.
Tank & Water Requirements
| Min Tank Size | 11 gallons |
| Temperature | 72–81°F |
| pH Range | 5.5–7 |
| Water Hardness (GH) | 2-10 |
| Bioload | low |
| Oxygen Demand | low |
| Plant Safe | yes |
| Aquarium Position | Mid |
Behavior & Activity
Classic mid-water schooler; smooth coordinated group swimming; gentle undulation; prefers planted areas with open lanes
Speed: 45/100Aggression: 1/10diurnalSchooling (8+)
Breeding
Difficult; egg depositor under leaves
Common Diseases
💊 Ich💊 generally hardy
Expert Notes
Classic schooling fish
Compatible Tank Mates
✓ betta fish✓ neon tetra✓ corydoras catfish✓ cherry shrimp✓ guppy✓ ember tetra✓ otocinclus✓ kuhli loach✓ dwarf gourami✓ mystery snail✓ nerite snail