Clown Rasbora (Rasbora kalochroma) Breeding Guide

Rasbora kalochroma is an egg-scattering continuous spawner from Sundaland blackwater, able to spawn in mature planted tanks but best controlled in dimly lit mesh-base setups.

Overview

Rasbora kalochroma, the clown rasbora, is a reddish cyprinid reaching about 10 cm, native to blackwater streams and peat swamps of Borneo, Sumatra and Peninsular Malaysia. According to Seriously Fish it is an egg-scattering, continuous spawner that exhibits no parental care and can spawn spontaneously in mature planted tanks.

Sexing

Seriously Fish reports that mature females are noticeably rounder-bellied and often a little larger than males. No other reliable external difference is documented.

Conditioning

The species takes bloodworm, Daphnia, Artemia and quality flakes or granules. A varied diet brings adults into spawning condition; controlled breeding still benefits from a dedicated setup.

Breeding Setup

Seriously Fish recommends a shallow, dimly lit container (about 75 x 30 x 30 cm) with a mesh base allowing eggs to fall through, plus java moss or fine-leaved plants. Temperature is kept at the upper range with slight acidity preferred.

Spawning Behavior & Trigger

As a continuous scatterer the fish disperse eggs that fall through the mesh out of reach of adults. Spawning can occur spontaneously in mature, well-planted tanks, though controlled breeding uses the dedicated container described above.

Egg & Fry Care

Incubation is temperature-dependent, usually 18-48 hours, with fry free-swimming 24-48 hours later. Initial food is Paramecium, progressing to Artemia nauplii and microworm.

Common Challenges

The species requires soft, acidic blackwater conditions, and egg predation by adults makes a mesh base or dense planting important. Small fry need correctly sized infusoria before they can take Artemia.