5 × Black Ruby Barbs (Pethia nigrofasciata)

This listing is for a group of 5 Black Ruby Barbs (Pethia nigrofasciata), also known as Ruby Barbs. They are active Sri Lankan shoaling fish with a compact barb body shape and attractive dark banding; mature males can develop much deeper ruby-black colour when settled and in good condition.

This pack contains five fish; we recommend a long-term group of at least six. Treat this five-fish pack as a starter or add-on pack rather than the final social group.

What you are buying

• Sale unit: 5 Black Ruby Barbs
• Scientific name: Pethia nigrofasciata
• Common names: Black Ruby Barb, Ruby Barb
• Supplied size: approximately 3–3.5 cm
• Adult planning size: about 5–6 cm
• Social plan: keep at least six where aquarium capacity allows
• Minimum aquarium guidance: around 80 litres for a group, with useful horizontal swimming room
• Temperature: 20–26°C
• pH: 6.0–7.5
• Hardness: around 2–20 dGH
• Temperament: active and generally peaceful when kept in an appropriate group
• Diet: omnivore

Appearance and colour

Black Ruby Barbs are not one flat colour throughout life. Juveniles and females tend to show more obvious dark vertical banding over a lighter body, while mature males can become dramatically darker with rich ruby-red to black tones, especially when settled, well fed and displaying around other members of the shoal.

That makes the species particularly effective in planted aquariums. Green plants, darker substrate and open swimming space help the group stand out. Product photographs should be treated as representative of the species and colour form rather than a guarantee that every individual will arrive showing mature male display colour.

Aquarium setup

Use a mature, fully cycled aquarium with stable filtration and enough horizontal space for the group to move together. Around 80 litres is a sensible starting point for a proper shoal, but tank dimensions, hardscape, existing livestock and filtration still matter. A heavily decorated 80-litre tank with little open water is not equivalent to one with a useful swimming footprint.

Planting around the sides and back works well. Leave a clear midwater lane where the barbs can move as a group. Wood, taller plants and floating cover can create shaded areas and line-of-sight breaks without turning the aquarium into a maze.

Black Ruby Barbs are active fish, so avoid layouts designed only around still, delicate long-finned tank mates. The aquarium should give the shoal enough room to direct most of its social energy toward its own group.

Water parameters

Keep the water stable within a practical tropical-to-warm-temperate range. Aim for 20–26°C, pH 6.0–7.5 and hardness around 2–20 dGH. These values are useful screening ranges, not permission to make sudden chemistry changes simply to reach a number.

Test the source water and aquarium water before ordering. Ammonia and nitrite should remain at zero in a mature system, and water changes should be guided by measured water quality and total stocking.

Feeding

Black Ruby Barbs are omnivores. Use a high-quality flake, small pellet or granule as the staple, then add suitable frozen foods such as daphnia, brine shrimp or bloodworm in moderation. Vegetable-based foods can add useful variety.

Because the species is active and confident at feeding time, distribute food so the whole shoal has access. Several modest feeds or a carefully measured routine are better than allowing excess food to settle into the substrate and degrade water quality.

Behaviour and social needs

These are shoaling barbs, not fish to keep singly or as a token pair. A proper group spreads social interaction across the shoal and usually produces better confidence, colour and behaviour. In an undersized group, active barbs can become more pushy toward tank mates.

We recommend six or more where the aquarium can support them. If you buy this five-fish pack, plan either to add to an existing Black Ruby Barb group or to combine it with another appropriate quantity so the final shoal meets the social target.

Tank mates

Choose robust, peaceful community fish that enjoy similar water and can cope with active midwater companions. Suitable barbs, danios, rasboras, some loaches and other medium community fish can work when adult size and water needs overlap.

Avoid cramped combinations with slow, delicate long-finned fish, especially if the Black Ruby group is too small. Also avoid large predators and highly territorial species that can intimidate the shoal or treat smaller barbs as prey.

Why five fish can still be a useful product

This five-fish pack can make sense for an aquarist who already keeps Black Ruby Barbs and wants to increase the group, or for someone intentionally buying more than one pack for a suitably sized aquarium.

Before ordering

Choose this pack if you have a mature aquarium with open swimming space and a plan for a final shoal of at least six. Reconsider if the aquarium is newly set up, already crowded, or dominated by slow long-finned fish that would be stressed by a very active barb group.