Pearly Rasbora (Rasboroides vaterifloris) Breeding Guide

Breeding the Sri Lankan Rasboroides vaterifloris: sexing, conditioning, a gentle planted spawning tank and rearing the slow-growing fry.

Overview

Rasboroides vaterifloris is an endemic Sri Lankan cyprinid that, per Seriously Fish, is a typical egg-scattering free spawner exhibiting no parental care. Females release eggs in batches of roughly 20 over several spawning events before becoming exhausted, and the fry are reported to be slow-growing, taking several months to reach maturity.

Sexing

According to Seriously Fish, adult males are noticeably smaller, slimmer and more colourful than females, with the difference especially clear when males are in spawning condition.

Conditioning

Condition adults well before spawning. Seriously Fish describes introducing 5-6 well-conditioned adult pairs to the breeding tank rather than relying on a single pair, improving the chance of productive spawns.

Breeding Setup

Dedicated breeding tank with fine-leaved plants such as Taxiphyllum species for egg deposition and fish security.
Very gentle filtration; an air-powered sponge unit is best so it does not draw in eggs or fry.
Soft, slightly acidic water; the species' recorded natural range is 23-27 C, pH 5.5-7.0 and 18-143 ppm hardness.
Some breeders reduce water depth to about 10 cm (4 inches) for fry rearing (Seriously Fish).

Spawning Behavior & Trigger

Allow the conditioned pairs to spawn naturally for 4-5 days before removing them. The fish scatter eggs among the plants in successive small batches of about 20 with no nest or guarding behavior (Seriously Fish).

Egg & Fry Care

Eggs hatch within 24-48 hours and the fry become free-swimming after 3-5 days. Offer Paramecium as a first food, then progress to Artemia nauplii and microworms as the fry grow (Seriously Fish).

Common Challenges

The fry are said to be slow-growing and take several months to reach maturity, so stable soft water and a sustained supply of tiny foods are needed throughout rearing. Gentle, egg-safe filtration is essential to avoid losses.