Black Ruby Barb

Pethia nigrofasciata

Also known as: Ruby barb, Purple-headed barb

Water Parameters

• Temperature: 20–26°C
• pH: 6–7.5
• Hardness (GH): 36–214 ppm (2–12 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A peaceful, cool-tolerant barb from Sri Lanka whose displaying males are a remarkable transformation: out of condition they are a modest silver-grey with dark bars, but in courtship and dominance contests the front half of the body flushes a deep, velvety ruby-red over an almost black ground, one of the more dramatic colour changes in the hobby. The colour is the reward for a settled group of six or more, ideally with several males competing for attention. Unlike its notorious tiger barb cousin it is genuinely community-safe, with only the mild nipping common to under-grouped barbs. Hardy, active, undemanding, and happy in cooler water, it is an excellent and underused choice for a planted community.

Tankmates

A peaceful, well-mannered barb, in clear contrast to the tiger barb, best kept in a group of at least six where the males display and colour up. Small groups can show a mild fin-nipping tendency, redirected harmlessly into the school once numbers are adequate, so it is still wise to avoid slow, long-finned tankmates such as bettas, fancy guppies, and angelfish. Excellent with other peaceful barbs, danios, and corydoras, and its tolerance of cooler water suits unheated or lightly-heated community tanks. Shows best colour in a planted tank with subdued light.

Compatible with

• Cherry Barb
• Gold Barb
• Odessa Barb
• Rosy Barb
• Bronze Corydoras
• Zebra Danio
• Bristlenose Pleco

Avoid keeping with

• Betta
• Long Finned Species
• Guppy
• Angelfish

Common Problems

• dull colour out of breeding condition or in small groups
• mild fin nipping when under-grouped
• ich
• stress when kept too warm long-term

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20