Rasbora Kalochroma Clown Rasbora Care Guide: Borneo Wild
Stand the clown rasbora next to its smaller cousins and the size jump is immediately obvious — at 8-10 cm adult length, this is one of the largest rasboras in the trade and behaves more like a small barb than a typical micro-shoaler. Rasbora kalochroma wears a striking burgundy-red body marked with two distinctive black spots, one mid-flank and one at the tail base, on top of glassy iridescent scales. The rasbora kalochroma is best treated as a semi-shoaler — keep at least five but expect them to spread out rather than tight-school. This guide from Gensou Aquascaping at 5 Everton Park covers parameters and sourcing.
Origin and Habitat
The species inhabits blackwater forest streams of Borneo, Sumatra, and the southern Malay Peninsula. Habitat is heavily shaded peat swamp with deep leaf litter, water pH 4.5-6.0, conductivity 20-50 microsiemens, and 24-28°C. Adults occupy slightly faster-flowing channels than smaller rasbora species and forage along leaf litter.
Tank Size
A group of five to seven adults needs 150-200 litres due to large size and territorial spacing behaviour. Smaller tanks lead to chronic stress and chasing. Length matters — 100 cm minimum, with 120 cm preferred for stable groups.
Aquascape
Build a heavily wooded blackwater scape with multiple driftwood structures, deep leaf litter, fine dark sand, and shade-tolerant plants like Java fern, Anubias and crypt species. Floating salvinia dims the surface and reduces stress colouration loss. Layer ANS Catappa Leaves Large from the botanical range across the substrate.
Water Parameters
Target pH 5.0-6.5, GH 1-5, KH 0-2, temperature 26-28°C. Wild imports demand acidified soft water for the first six months; once acclimated they tolerate slightly higher pH but never above 7.0 long-term. Singapore PUB tap modified with peat extract and aged catappa works for established adults.
Filtration
Moderate to gentle flow. A small to medium canister or quality HOB on a 150-200 litre tank handles waste loads from larger fish without creating excessive surface chop. The aquarium filtration range covers options sized for medium planted communities.
Feeding
Carnivorous-leaning omnivore. Quality pellet, frozen bloodworm, frozen mysis, live blackworm and chopped earthworm all accepted enthusiastically. Larger food items than typical rasboras require — clown rasboras have a sizeable mouth and prefer chunky prey. The community fish food range includes appropriate medium-pellet options.
Behaviour
Semi-shoaling rather than tight-schooling. In groups of five or more they maintain loose social structure with constant low-level chasing and territorial displays. Single specimens become reclusive and lose colour. Mixed-sex groups show occasional spawning behaviour in mature tanks.
Tank Mates
Compatible with chocolate gouramis, larger tetras, peaceful catfish, and small to medium SE Asian community fish. Avoid pairing with very small or very shy species — the active chasing of clown rasboras stresses delicate fish. Wild bettas tolerate them but smaller rasbora species (Sundadanio, Boraras) get bullied at feeding time.
Breeding
Egg-scatterers requiring soft acidic water and dense fine-leaved plants or spawning mop. Adults eat eggs aggressively. Fry need very small live food (infusoria, then microworm) for the first two weeks. Captive breeding is uncommon — most stock remains wild caught.
Singapore Sourcing
Iwarna and the occasional Polyart shipment bring in wild Bornean clown rasboras at SGD 8-15 per fish. Buy in groups of five or six minimum for stable behaviour. House the group in a 120 cm tank from the aquarium tank range with a tight lid — like most rasboras they jump when startled.
Why Clown Rasboras Earn Their Tank Space
The combination of bold colouration, real visual presence at 10 cm body length, and biotope accuracy with larger blackwater communities makes clown rasboras a strong centrepiece species for keepers wanting something more substantial than chilli rasboras or harlequins. They pair particularly well with chocolate gourami breeding tanks where the dither value is high without stressing the gouramis.
Related Reading
emilynakatani
Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
