The Black Ruby Barb is a Sri Lankan endemic with striking black bars and ruby-red males, a hardy and peaceful addition to any community tank.
Overview
The Black Ruby Barb (Pethia nigrofasciata) is one of the most beautiful yet undemanding fish in the Cyprinidae family. This species is endemic to the shaded mountain streams and small rivers of southwestern Sri Lanka, where it inhabits slow-flowing areas among fallen leaves and driftwood. In the wild, populations face pressure from habitat loss, making captive breeding particularly valuable for species conservation.
Adults reach 5–6 cm in length. The main attraction of this fish is the stunning contrast between the deep ruby-red body of males and three bold black vertical bars. Females are more modestly colored in golden-yellow tones with the same dark bars. During spawning, males develop an exceptionally intense, almost burgundy coloration — the very feature that earned the species its common name. With proper care, these barbs live 4–6 years.
By temperament, this is a schooling and peaceful fish, perfectly suited for community aquariums. I recommend keeping a group of at least 6–8 individuals — in a school, the fish feel more confident, and males display their magnificent colors more actively as they compete with one another.
Tank Requirements
A school of Black Ruby Barbs requires an aquarium of at least 60 liters. Optimal water parameters are: temperature 20–25°C, pH 6.5–7.5, and general hardness (GH) 5–19. The species is quite flexible regarding water chemistry, making it an excellent choice for beginner aquarists.
When setting up the tank, aim to recreate conditions close to the natural habitat: dense vegetation along the perimeter, several pieces of driftwood and rocks, and subdued lighting or floating plants to create shaded areas. Be sure to leave an open swimming zone in the center — these barbs are active during the day and enjoy darting around open spaces. A dark substrate will beautifully highlight the vivid coloration of the fish.
Filtration should be moderate — these fish do not appreciate strong currents. An internal filter or a small external filter with a flow diffuser works best.
Feeding and Diet
The Black Ruby Barb is a typical omnivore that causes no feeding difficulties. The staple diet should consist of high-quality flakes or small pellets. To maintain vibrant coloration and overall health, I recommend regularly supplementing with live or frozen foods: bloodworms, brine shrimp, daphnia, and cyclops.
Feed 2–3 times daily in small portions that are consumed within 2–3 minutes. Do not neglect the plant-based component — these barbs readily eat blanched spinach, zucchini pieces, and spirulina. A varied diet is the key to healthy, brilliantly colored fish.
Care and Maintenance
Caring for Black Ruby Barbs is straightforward, reflecting their low care-level requirements. The foundation of successful keeping is regular weekly water changes of 25–30%. Monitor water parameters using test kits: ammonia and nitrites should be at zero, and nitrate levels should not exceed 20–30 mg/l.
Keep the substrate clean by vacuuming it during water changes. Check the filter regularly and rinse filter media in removed tank water (never under tap water!). These fish are quite hardy, but poor water quality can lead to ich and bacterial infections. When basic maintenance rules are followed, health issues rarely arise.
Compatibility
The Black Ruby Barb is one of the most peaceful barb species, making it an excellent companion for many fish. It gets along wonderfully with other peaceful schooling species: Cherry Barbs, Neon Tetras, Harlequin Rasboras, and Zebra Danios. Among bottom dwellers, Corydoras make great tank mates. They can also be kept with Dwarf Gouramis and Ram Cichlids.
Avoid housing them with large, aggressive cichlids or fish with long, flowing fins — although the Black Ruby Barb is far calmer than the Tiger Barb, it may show interest in other fishes' fins under stressful conditions. Keeping them in a sufficiently large school (6 or more) virtually eliminates this behavior.
Breeding
Breeding Black Ruby Barbs is a moderately challenging task, quite achievable even for beginners. Prepare a separate breeding tank of 20–30 liters with soft, slightly acidic water (pH 6.5, GH 5–8) and a temperature 1–2 degrees above the usual range (24–25°C). Place fine-leaved plants or a spawning grid on the bottom to protect the eggs.
For 1–2 weeks before spawning, feed the breeding pair generously with live foods. A male ready to spawn develops a stunning dark ruby, almost black coloration — a truly impressive sight. The female becomes noticeably plumper with eggs.
Spawning typically occurs in the morning. The female lays 100–200 eggs that sink to the bottom among the plants. Remove the parents immediately after spawning, as they tend to eat their own eggs. The larvae hatch within 24–36 hours, and after 3–4 days the fry become free-swimming. First foods should be infusoria and brine shrimp nauplii. Gradually transition to larger foods as the fry grow.