The red side barb (Pethia nigrofasciata) is a small fish native to Sri Lanka where it is known from the Nilwala River drainage but also is widely distributed throughout river basins of southern India in the states of Tamil Nadu, Kerala, Karnataka, Andhra Pradesh, and Maharashtra. It inhabits a variety of habitat types, from flowing hill streams to quiet stretches in the middle reaches of rivers, but tends to be absent from lowland environments and in Sri Lanka it is apparently one of the few freshwater fishes found in mountain streams at over 1500 meters of elevation. .This fish grows to an adult size of up to 2 inches long. Mature males are noticeably smaller, slimmer, and more colorful than females, especially when in breeding condition.
The red side barb should be maintained in an aquarium of 29 gallons or larger. Smooth rocks, driftwood (ZM2000) and live or artificial plants may be used, as well as a sand substrate (CS7538). These fish look great in a heavily planted tank with a dark substrate and floating plants to diffuse some of the light..
The red side barb prefers a temperature of 64°F to 76°F, a pH of 6.0 to 7.5, and a hardness of 3 to 13°H. Be sure water is clean and well oxygenated.
The red side barb is a generally a peaceful fish suitable for a community aquarium. Good tank mates include other peaceful barbs, tetras, pencil fish, cory cats, apistogrammas, rams, small loricariids, and rasboras. Black ruby barbs should be kept in schools of at least 6 to 10 individuals to promote schooling behaviors and encourage males to color up.
The red side barb is easy to feed in the aquarium and will readily accept just about any frozen appropriately sized food item such as flakes containing algae (AL165) and frozen brine shrimp (SF6777). For maximum color, growth, and health these fish will look their best when given probiotics (AL169) in addition to a balanced diet.