Overview
The Harlequin Rasbora (Trigonostigma heteromorpha) is a freshwater fish from the family Cyprinidae. It thrives at temperatures of 22–27 °C with a pH of 6.0–7.8, requiring a minimum tank size of 60 litres. Classic community fish with a distinctive black triangular patch. Schools tightly near the surface; looks stunning in large groups of 10+.
Scientific Classification
| Rank | Classification |
|---|---|
| Family | Cyprinidae |
| Genus | Trigonostigma |
| Species | Trigonostigma heteromorpha |
| Water type | freshwater |
Natural Habitat
Appearance
Behavior
Schools tightly near the surface; looks stunning in large groups of 10+
| Trait | Value |
|---|---|
| Temperament | Classic community fish with a distinctive black triangular patch |
| Schooling | Yes |
| Activity level | active |
Water Requirements
| Parameter | Ideal Range | Notes |
|---|---|---|
| Temperature | 22–27°C (72–81°F) | Use a reliable adjustable heater |
| pH | 6–7.8 | Avoid sudden swings |
| Hardness (GH) | soft dGH | Soft to moderately hard |
| Ammonia | 0 ppm | Any detectable ammonia signals a problem |
| Nitrite | 0 ppm | Toxic even at low levels |
| Nitrate | <20 ppm | Manage through regular partial water changes |
| Min. tank | 60L (16 gal) | Larger tanks are easier to keep stable |
Interesting Facts
- One of the most popular aquarium fish in the hobby for over 100 years
📋 Full Care Guide
Ready to set up a tank for your Harlequin Rasbora? The complete care guide covers tank setup, feeding schedule, common diseases, tank mates, and breeding.
Read Harlequin Rasbora Care Guide →Related Species
Related Species & Guides
This species profile was reviewed for biological accuracy and practical aquarium care guidance. For suspected illness or disease, test your water parameters first and consult an aquatic veterinarian if symptoms persist.