Product Details

Black Ruby Barb – Pethia nigrofasciata

The Black Ruby Barb is a beautiful, active barb known for its deep ruby-red body colour and dark charcoal-black markings in mature males. Also sold as the Purplehead Barb, Pethia nigrofasciata is calmer than Tiger Barbs but still needs a proper group, clean water and plenty of swimming space. It is an excellent choice for planted community aquariums where a lively but not overly aggressive barb is wanted.

Key Identification:

Common Name: Black Ruby Barb
Other Names: Ruby Barb, Purplehead Barb, Black-banded Barb, Black Ruby, Ruby Black Barb
Scientific Name: Pethia nigrofasciata
Older / Trade Names: Puntius nigrofasciatus, Barbus nigrofasciatus
Fish Type: Barb / Cyprinid
Water Type: Freshwater

Natural Range & Habitat:

Pethia nigrofasciata is native to Sri Lanka, especially clear, shaded forest streams and river margins in the south-western wet-zone drainages. Natural habitats are generally cool for a tropical fish, clean, well oxygenated and shaded, with gravel, sand, leaf litter, vegetation and quieter marginal pools.

In the aquarium, Black Ruby Barbs do best in mature planted setups with open swimming room, shaded areas, darker décor and steady filtration. They appreciate clean, oxygen-rich water and should not be kept in hot, stagnant or poorly maintained aquariums.

Appearance & Adult Size:

Black Ruby Barbs have a deep barb body with dark vertical banding and a warm silver, gold, red or purple body tone. Mature males can become especially impressive, developing a dark head and body with rich ruby-red to purple-red colouration, particularly when displaying. Females are usually fuller-bodied, paler and more golden or striped.

Adults usually reach around 5–6 cm. Colour improves with age, good diet, stable water and mixed-sex group keeping.

Aquarium Suitability:

This is a good species for peaceful to moderately active community aquariums, planted barb displays and cooler tropical setups. Black Ruby Barbs are more manageable than many nippy barbs, but they are still active shoaling fish and need room to move.

They are not suitable for tiny aquariums, very warm discus-style tanks, aggressive cichlid setups, predator communities or very quiet nano displays. They are usually safer with long-finned fish than Tiger Barbs, but calm, fin-safe tank mates are still the best choice.

Recommended Aquarium Size:

A practical minimum is 90–120 litres for a group, with a tank length of at least 80 cm recommended. Larger aquariums are better for bigger groups and mixed communities.

Keep in a group of at least 6, with 8–10 or more preferred. A larger group improves confidence, spreads male display behaviour and helps the fish show better colour.

Water Conditions:

Temperature: 20–26°C
pH: 6.0–7.5
Hardness: Soft to moderately hard
Additional Notes: Black Ruby Barbs prefer clean, stable, well-oxygenated water. They are not a high-temperature species and should not be kept long term in overheated aquariums. Regular water changes, good filtration and shaded planted areas are recommended.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Black Ruby Barbs are generally peaceful, active community fish. Suitable tank mates include danios, peaceful rasboras, larger tetras, Cherry Barbs, Rosy Barbs in compatible temperatures, Cory-type catfish, bristlenose plecs, hillstream loaches in suitable setups and calm community fish that enjoy clean, well-oxygenated water.

Avoid large predators, aggressive cichlids, very shy nano fish and delicate slow feeders that may be intimidated by active barbs. They should not be kept singly or in pairs, as this reduces confidence and can make behaviour less predictable.

Feeding:

Black Ruby Barbs are omnivorous, with a strong natural interest in plant matter, algae and detritus. Offer quality flakes, small granules or micro pellets as the staple diet. Include vegetable-based foods such as spirulina flakes, algae wafers or blanched greens, and supplement with frozen or live foods such as daphnia, cyclops, brineshrimp, mosquito larvae and small bloodworm.

A varied diet with some vegetable content helps maintain colour, digestion and condition.

Behaviour in the Aquarium:

This species usually swims through the middle and lower areas of the aquarium, moving between plant cover and open water. Males may display to females and rival males, becoming much darker and redder when settled. Some chasing and sparring is normal, but it is usually manageable in a spacious aquarium with a good-sized group.

Black Ruby Barbs are egg scatterers and do not provide parental care. If spawning occurs in a community aquarium, eggs and fry are usually eaten unless a separate breeding setup is used.

Care Notes:

Add Black Ruby Barbs only to a mature, fully cycled aquarium. Provide plant cover, shaded areas, open swimming space and regular maintenance. Avoid prolonged high temperatures, poor oxygenation and cramped conditions.

This species often looks dull when young or stressed, but mature males can become extremely colourful once settled into a planted aquarium with females present and good water quality.

Recommended For:

Beginner to intermediate

Availability:

Common to occasional / Usually captive-bred or farmed

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, red colour, black coverage, banding, body tone and markings can occur between individual fish.