Species profile
Black Ruby Barb
Pethia nigrofasciata
Peaceful
Easy care
100 L minimum aquarium
5–6 cm adult size
Midwater
Minimum group: 6
About this species
General notes for hobby use.
Active Sri Lankan shoaling barb; peaceful in a proper group but may sample very fine plants and should not be cramped with long-finned fish.
Water parameters
Suggested general range for long-term care.
Temperature
18–26 °C
pH
5.5–7
GH
Up to 15 dGH
KH
Not yet documented
Flow preference
Low–moderate
Data confidence
Verified
Behaviour
General behaviour traits used by TanksConnected compatibility checks.
Minimum group size
Minimum group: 6
Tank zone
Midwater
Territory level
Low
Predation risk
Tiny fry
Bioload factor
1.2
Maintain a good-sized group to keep social interactions within the shoal. Males intensify dramatically in colour when displaying.
Compatibility flags
Quick cautions for common tank-planning issues.
Fin nipper
No
Plant safe
Caution
Shrimp safe
No / caution
Snail safe
Yes
Cave breeder
No
Digs substrate
No
Jump risk
Yes
Natural history & care
Research-backed context for long-term aquarium care.
Lifespan
Not yet documented
Diet type
Omnivore
Minimum aquarium volume
100 L
Minimum footprint
80 × 35 cm
Accepted scientific name
Pethia nigrofasciata
Alternative names
Black Ruby Barb, Ruby Barb, Purple-headed Barb
Native range
Endemic to Sri Lanka.
Natural habitat
Forest streams with shade, leaf litter, stones, wood and seasonal flow changes.
Diet & feeding
Generalist omnivore taking small invertebrates, algae/plant material and prepared foods.
Breeding & sexing
Research-backed guidance for identifying sexes and reproductive behaviour.
Sexing
Adult males develop the characteristic dark head and intense ruby/red body; females remain fuller and less intensely coloured.
Breeding
Egg scatterer capable of producing large clutches; eggs can hatch in roughly 24–36 hours under warm spawning conditions.