Not furry, but we like them anyway.

Black Ruby Barb

Pethia nigrofasciata

Also called Purplehead barb

SpeciesShort profile

From Sri Lanka (endemic): shaded forest streams of the southwestern wet zone, from the Kelani to the Nilwala river basins, up to about 300 m elevation1 2 3

At a glance the quick version

Length5.5 to 6.7 cm1 2 3

Sizesmall

Seriously Fish gives 5.5 cm SL; FishBase gives 6.0 cm TL for males and 6.7 cm TL for females

Very peaceful

Stunning breeding colours

Active schooler

1 3

Looks how to spot one

Deep-bodied scaled cyprinid

A deep-bodied barb with three dark vertical bars on a yellowish-grey body. Males in breeding colour turn a deep ruby to purple-red at the front with a dark rear body and a black dorsal fin. Females stay paler and are larger and fuller than males.1 3 2

Coloursyellowish greyblack vertical barsruby red to purple (breeding males)black fins1 3

Personality what they are like

Very peaceful and sociable, it suits a community tank with other gentle fish.1

Daily activity how busy a day looks

A lively schooling swimmer that needs swimming room between planted areas.1 3

Grooming and care the hands-on bits

Keep the water clean and soft with regular partial changes. Leaf litter and shade bring out its colour.1

Home where they are happiest

A tank with a base of at least 80 x 30 cm (about 72 litres). Temperature 20-27 °C (FishBase 22-26 °C), pH 5.5-7.5 (FishBase 6.0-6.5), hardness 2-15 °H. Sand, leaf litter, wood and dense planting copy its forest streams.1 2

Food basics what goes in the bowl

Forages on algae, detritus and small invertebrates in the wild. Offer quality flakes or granules with algae content plus small live or frozen foods such as bloodworm, Daphnia and Artemia.1 2

Company who they like around

Keep a group of at least 6-10. Good tankmates include tetras, livebearers, rainbowfish, small catfish and loaches.1

The story where it all began

Albert Günther described the black ruby barb in 1868 from Sri Lanka. It has long been a popular aquarium fish that breeds well in captivity, and Sri Lanka no longer allows wild fish to be exported.2 1 3

Fun facts for the dinner table

1
Breeding males change from barred yellow-grey to a rich ruby and purple colour.3
2
Its eggs hatch in one to two days and the fry swim freely a day later.2
3
It lives only in Sri Lanka, in streams shaded by rainforest.2
4
Sri Lanka protects it by banning the export of wild fish.1

Recognised by the official bits

IUCN Red List: Assessed as Vulnerable (August 2019)2
FishBase: Described by Günther in 18682
Sri Lanka: Export of wild-caught specimens from Sri Lanka is prohibited1

The care rhythm a typical week and year

A typical home-care rhythm for a Black Ruby Barb. A starting point, not a vet's advice.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Water changeAbout 25% of the waterevery week
Water testevery week
Glass cleanevery week
Filter rinseRinse in old tank water, never tap waterevery month

Owner questions the things everyone asks

How often should I feed my Black Ruby Barb?

Furry Diary's starting plan is to feed small amounts once or twice a day. Offer quality flakes or granules with algae content plus small live or frozen foods like bloodworm and Daphnia. For exact amounts, check the food label and ask your vet.1 2 Pet Wiki plan

What does a Black Ruby Barb eat, and what should it never eat?

In the wild they forage on algae, detritus and small invertebrates. At home offer quality flakes or granules with algae plus small live or frozen foods such as bloodworm, Daphnia and Artemia. Avoid feeding anything that is not designed for fish, and never give human food or large pieces that could cause harm.1 2

How much space does a Black Ruby Barb need?

They need a tank with a base of at least 80 x 30 cm, which is about 72 litres. This gives them the swimming room they need as lively schooling fish. A larger tank is always better for a group of 6-10.1 2

What temperature, light or water does a Black Ruby Barb need?

Keep the water temperature between 20-27°C (FishBase says 22-26°C), pH 5.5-7.5 (FishBase 6.0-6.5), and hardness 2-15°H. Soft, clean water with leaf litter and shade brings out their colour. Use a sand substrate, wood, and dense planting to copy their forest stream home.1 2

How often should I clean a Black Ruby Barb's home?

Furry Diary's plan suggests a weekly partial water change of about 25% and a weekly glass clean. Also test the water weekly and rinse the filter in old tank water (never tap water) once a month. Keep the water clean and soft with regular partial changes.1 Pet Wiki plan

Can a Black Ruby Barb live with others?

Yes, they are very peaceful and sociable, perfect for a community tank. Keep a group of at least 6-10 of their own kind. Good tankmates include tetras, livebearers, rainbowfish, small catfish and loaches.1

How long does a Black Ruby Barb live?

Their lifespan varies depending on care and environment. For a reliable estimate, ask a good breeder or an exotic-pet vet. With proper care they can live several years.

Can I handle a Black Ruby Barb?

It is best not to handle them as they are delicate fish and handling can cause stress or injury. Enjoy watching them swim in their tank instead. If you need to move them, use a soft net and keep them in water.1

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

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Where this comes from

Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.

Seriously Fish - Pethia nigrofasciata seriouslyfish.comused for origin, size, tank and water parameters, diet, behaviour, appearance, export ban
FishBase - Pethia nigrofasciata fishbase.seused for author/year, IUCN status, size, water parameters, habitat, spawning
Wikipedia - Black Ruby Barb en.wikipedia.orgused for other names, colours, size

Checked 2026-09-30. Text is written in our own words from these sources.