Black Harlequin Rasbora (Trigonostigma heteromorpha ‘Black’) is a striking freshwater fish variant with a deep black triangular marking contrasting sharply against a darker or copper-toned body. Peaceful and active, it is perfect for community tanks and schooling setups.
Out of Stock
Black Harlequin Rasbora (Trigonostigma heteromorpha ‘Black’) is a striking freshwater fish variant with a deep black triangular marking contrasting sharply against a darker or copper-toned body. Peaceful and active, it is perfect for community tanks and schooling setups.
Copper to dark-toned body with a bold, deep black triangular patch starting behind the dorsal fin and extending toward the tail. Laterally compressed, streamlined body with transparent fins. Males are slightly slimmer and more intensely colored; females are slightly rounder with paler tones.
4–6 years with proper care
Omnivorous; feeds on high-quality flakes, micro pellets, frozen foods, and live foods such as daphnia, brine shrimp, and micro worms. Occasional blanched vegetables like zucchini or spinach enhance health and coloration.
Black Harlequin Rasboras are ideal for aquariums requiring peaceful, social, and visually unique schooling fish. They add charm, contrast, and dynamic movement to planted community tanks.
Beginner to Intermediate – hardy but prefers stable water and schooling conditions.
20+ gallons (for a small school)
6.0 to 7.5
2–15 dGH
72–81°F (22–27°C)
2 inches
Other Harlequin Rasboras, small tetras, dwarf gouramis, peaceful danios, and other Rasbora species. Avoid aggressive or large fish.
Large, aggressive, or fin-nipping species that may stress or harm them.
Trigonostigma heteromorpha
Cyprinidae
Southeast Asia – Malaysia and Singapore; shallow, slow-moving streams with dense vegetation.
Highly social; best kept in schools of 6 or more. Peaceful and compatible with other small community fish.
Feed 2–3 times daily with flakes, micro pellets, frozen/live foods. Occasionally supplement with finely chopped or blanched vegetables for optimal health and coloration.
Egg-scatterer; deposits eggs among fine-leaved plants or spawning mops. Adults do not guard eggs. Condition males and females with protein-rich foods before spawning. Fry feed on infusoria or newly hatched brine shrimp.
pH: 6.0–7.5, Temperature: 72–81°F (22–27°C), Hardness: 2–15 dGH, Ammonia/Nitrite: 0 ppm, Nitrate: <20 ppm
Sensitive to poor water quality; prone to ich, stress-related illnesses, and fin damage if kept with aggressive species. Maintain clean water, proper diet, and suitable school size.
Peaceful, social, and active. Best kept in schools of 6–10 individuals to encourage natural schooling behavior and reduce stress. Compatible with other peaceful mid-level community fish.
A variant of the classic Harlequin Rasbora, the Black Harlequin is native to Southeast Asia, mainly Malaysia and Singapore. It inhabits slow-moving streams with dense vegetation. Adults reach up to 2 inches and thrive in planted tanks with moderate water flow and open swimming areas. Ideal for aquarists seeking a peaceful, visually striking schooling fish.