Arulius barb (Dawkinsia arulius) care guide

Group

Freshwater fish

Other names

Arulius barb, Puntius arulius, Systomus arulius

Family

Cyprinidae (Smiliogastrinae, small barbs)

Origin

Karnataka, south-western India: upper Cauvery (Kaveri) around Kodagu and the upper Tungabhadra; clear, well-oxygenated rocky streams and rivers.

Water

freshwater

Maximum size

10 cm

Temperature

19–25°C

pH

6–7.5

Hardness

Soft to medium, 2–10 dGH

Minimum tank

162 litres

Care level

beginner

Temperament

peaceful

Care

The arulius barb is an active, peaceful shoaling barb that should be kept in a group of at least 8–10; in small numbers it can become nippy and nervous. It grows to about 10 cm and needs swimming room, so give it a tank with a base of at least 120 × 45 cm (around 162 litres). Set the tank up like a clear flowing stream, with sand, fine gravel, water-worn rocks and a few small boulders, plus driftwood and hardy plants such as Java fern (Microsorum), Bolbitis or Anubias attached to the decor. Provide good water movement and plenty of oxygen. It prefers slightly cooler water than many tropical fish: about 19–25 °C, pH 6–7.5 and 2–10 dGH. Because it comes from clean water it does not cope with a build-up of waste, so filter well and change 30–50% of the water every week. The body is silvery-olive with three dark blotches: one in the middle of the body, one above the anal fin and one at the tail base. Adults, especially males, may show extended dorsal-fin rays. Males are more colourful and grow small white tubercles on the head at spawning time; females are slightly larger, heavier-bodied and duller. It is often confused with D. tambraparniei, whose males have long dorsal filaments, and some fish sold as arulius barbs are actually that species. In the wild it now survives only in a small area, having apparently disappeared from its original locality near Srirangapatna after a dam was built. It was listed as Endangered by the IUCN in its 2010 assessment, so captive-bred stock is preferable. It was moved from Puntius into Dawkinsia in 2012. Sources: Seriously Fish (seriouslyfish.com/species/dawkinsia-arulius/); FishBase (fishbase.se/summary/Dawkinsia-arulius.html); Wikipedia (en.wikipedia.org/wiki/Dawkinsiaarulius). Checked October 2026.

Diet

An omnivorous forager that eats worms, insects, crustaceans and plant matter in the wild. In the aquarium offer good-quality dried flakes and granules together with regular small live and frozen foods such as bloodworm, Daphnia and Artemia.

Breeding

An egg-scatterer with no parental care that will eat its own eggs. Spawning is most likely in slightly acidic to neutral water at the warmer end of the range. Use a dimly lit tank with a mesh base or a thick layer of fine-leaved plants or spawning mops, add a well-conditioned pair or small group, and remove them once spawning is over. The eggs hatch in 24–48 hours and the fry swim freely about a day later. Feed microscopic foods first, then microworm and newly hatched brine shrimp.

Compatibility and tank mates

Peaceful but bold and active, so best with similar-sized, robust fish from flowing water: other medium-sized barbs such as rosy barbs, danios and loaches. Very small fish such as neon tetras may be eaten, and slow or long-finned fish may be harassed if the barbs are kept in too small a group.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.