
Pethia nigrofasciata
20-27 °C
5.5-7.5
5.5 cm
5 years
The black ruby barb is a stunning small cyprinid endemic to the southwestern 'wet zone' of Sri Lanka, where it is restricted to the Kelani and Nilwala river basins. Males in breeding condition develop a spectacular deep ruby-red head and anterior body contrasting with a jet-black posterior, making them one of the most attractive barbs in the hobby. Adults reach only 5-5.5 cm (2-2.2 inches), and export of wild specimens from Sri Lanka is currently prohibited, so all fish in the trade should be commercially bred.
This is a very peaceful, schooling species that should be maintained in groups of at least 6-10 individuals to bring out the best colour and social behaviour. A planted aquarium of at least 80 litres with a dark substrate, driftwood, and floating plants provides an ideal showcase for their colours. Filtration does not need to be particularly strong, though some water movement is appreciated. They are excellent community fish, compatible with similarly-sized tetras, danios, rasboras, and peaceful bottom-dwellers. Males will display intensely to one another during courtship without causing harm.
Water conditions: 20-27°C, pH 5.5-7.5, with soft to moderately hard water — farm-raised specimens are adaptable across this range. Diet is omnivorous: quality dried flakes and granules supplemented with small live and frozen foods such as bloodworm, Daphnia, and Artemia. Including vegetable matter in the diet enhances colour and condition. The black ruby barb is a prolific egg-scatterer with no parental care, and fry can be raised on infusoria and microworm. Its peaceful nature, stunning breeding colours, and manageable size make it a perfect choice for the planted community aquarium.
Pairwise screening against other species in the database (prioritizing the same family when data is available).
Review first (4)
Caution or avoid from automated rules — confirm before mixing.
| Species | Assessment | Notes |
|---|---|---|
| Chili Rasbora Boraras brigittae Caution | Caution | Fish 2x+ larger may eat smaller tankmates Open pair in Compare → |
| Reticulated Sae Crossocheilus reticulatus Caution | Caution | Fish 2x+ larger may eat smaller tankmates Open pair in Compare → |
| Siamese flying fox Crossocheilus oblongus Caution | Caution | Fish 2x+ larger may eat smaller tankmates Open pair in Compare → |
| Strawberry Rasbora Boraras naevus Caution | Caution | Fish 2x+ larger may eat smaller tankmates Open pair in Compare → |
| Species | Assessment | Notes |
|---|---|---|
| Blackline rasbora Rasbora borapetensis Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Cherry barb Puntius titteya Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Chinese barb Barbodes semifasciolatus Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Chinese Bitterling Rhodeus ocellatus Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Clown rasbora Rasbora kalochroma Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Fiveband barb Desmopuntius pentazona Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Melon Barb Pethia fasciata Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
| Slender Bitterling Tanakia himantegus Compatible | Compatible | No rule-based conflicts detected for this pair. Open pair in Compare → |
Same rule engine as Compare. Not a substitute for observation, tank size, or acclimation.
Keep this species? Spot anything off?