Black Ruby Barb (Purple-Headed Barb)

Puntius nigrofasciatus - Black Ruby Barb

The black ruby barb is a sleek looking fish that is best described as a friendly omnivore tank mate, that may have issues with large carnivore fish. It prefers soft, slightly acidic water, though it will do fine in a pH 7.0 as it does not like dirty water. The ruby barb is part of the minnow family. 

Origin and Distribution

The ruby barb originates from Sri Lanka, where it was once plentiful in the forest streams in the upper elevations of the Kelani and Niwala river basins. This native habitat is composed of dense vegetation and slow-moving waters, which are cooler than many tropical areas. The water in these streams is soft and acidic, and the river beds are composed of sand or fine gravel. Detritus and algae are the primary foods of the ruby barb in its natural habitat.

Unfortunately, populations have greatly diminished due to over-catching by those selling them for export in the aquarium trade. Rapid deforestation has also eliminated much of the original habitat of these beautiful fish. At one point they were on the brink of extinction but now have rebounded a bit. With proper conservation methods, they may remain as a viable population in the wild for generations to come.

Currently, the export of wild-caught ruby barbs from Sri Lanka is prohibited. All specimens sold in the aquarium trade are commercially bred, either in Sri Lanka or a number of other countries that commercially breed aquarium fish. This commercial breeding has resulted in the creation of a variety of new color and fin variations of the ruby barb.

Colors and Markings

Possessing a pointed head, high back, and deep body; the ruby barb is similar in body type to other banded barbs, such as the tiger barb. Three wide black bands run vertically through the body. In young fish, the body is pale yellow to yellow-gray. As the fish matures, the head becomes purple-red in color. In males, the entire body assumes this deep red color when they attain breeding age.

The entire dorsal fin will become deep black in males, while only the base of the dorsal becomes dark in females. Likewise, in males, the pelvic and anal fins will be black or red-black. In females, these fins will be far paler in color. Both sexes will pale in color when stressed, frightened, or are suffering from a disease or poor care. It is quite common for specimens in pet shops to appear washed out, then regain their bright coloration when taken to a quieter environment at home.

Adults will grow to a bit over 2 inches in length, with the males being slightly larger overall than females. They do not have barbels, which are whiskers from the mouth or nasal cavity, like other barbs.


Ruby barbs are schooling fish that should always be kept in groups of five or more. They are less nippy than the tiger barb and are suitable for community aquariums with other peaceful fish. Tetras, other barbs, danios, catfish, and gouramis can generally be safely kept with ruby barbs. Livebearers are also suitable tank mates. Ruby barbs make a nice contrast fish with schools of other vertically striped barbs, such as tiger barbs.

Ruby Barb Habitat and Care

In the wild, the ruby barb lives in the cooler slow-moving forest streams that are shaded by heavy vegetation. The water is soft and acidic, and the stream bottom is sandy with a layer of mulm (organic detritus). Replicating these conditions in the aquarium is ideal.

Keep the water temperature in the 72 to 79 F range and use floating plants to subdue the lighting. Use sand or small gravel for the substrate, preferably in darker colors. A live planted tank is ideal, although artificial plants will also suffice. Open space for swimming should be provided, as well as plenty of hiding places. Ruby barbs will become pale in color, and skittish if there are no hiding places to make them feel comfortable.

Ruby Barb Diet

Ruby barbs are benthic feeders or bottom feeders. They rummage for bits of organic material in the detritus that builds up on the bottom of the forest streams they live in. Their diet is almost entirely composed of the detritus and algae. For this reason, it’s important to keep plenty of vegetable matter in their diet. Flake foods high in vegetable matter, or vegetables such as shelled peas, pieces of raw zucchini, and blanched lettuce or spinach, are all good choices.

You can augment their primarily vegetarian diet with occasional feedings of live foods. Bloodworms, daphnia, and brine shrimp are all good choices to feed as a supplement every week or two.

Sexual Differences

As with many species, the male ruby barb is larger and more brilliantly colored the female particularly during spawning season. The fins of the males are darker. Females have a rounder belly and may be longer in overall length. The female does not undergo a significant color change when spawning.

Breeding the Ruby Barb 

Ruby barbs are egg-scatterers that may be bred in pairs or in groups. This species readily eat their own eggs and must be removed from the spawning tank once the eggs have been laid and fertilized. The water in the spawning tank should be soft, acidic, and from 77 to 82 F. Fine-leafed plants like java moss or spawning mops should be provided for the fish to scatter their eggs upon. Lighting should be very dim.

Breeding pairs or groups should be conditioned with plenty of small live foods. Frozen bloodworms and brine shrimp may be substituted if live food is not available. The male will develop intense deep ruby coloration throughout the entire body. The female will not change color; however, she will become plump as she fills with eggs.

Spawning begins with the male spreading his fins and swimming around the female in a courtship display. The process may take several hours from start to finish and produce as many as one hundred eggs. Once spawning is complete, the adult fish should be promptly removed from the tank. Shield the tank from light, as the eggs are sensitive to light. 

The eggs will hatch in approximately 24 hours, and the fry will become free swimming in another 24 hours. Initially, the fry will consume infusoria or commercially prepared fine fry food. Within a few days, they may be fed freshly hatched brine shrimp. If the eggs fail to hatch, make sure the spawning pair are well conditioned with high-quality foods before the next spawning. It is believed inadequate diet is responsible for many spawning failures.

More Pet Fish Breeds and Further Research

If ruby barbs appeal to you, and you are interested in some compatible fish for your aquarium, read up on: