Boraras naevus

Overview

A peaceful miniature cyprinid from southern Thailand, Boraras naevus is best suited to quiet, densely planted surroundings. The dark patch on the front of each flank is substantially larger in males than females, making sexual differences useful for identification.

Distribution & habitat

Confirmed localities lie in the lower Tapi drainage of Surat Thani province, on the Gulf of Thailand side of the peninsula. Shallow, clear swamps and marshes provide habitat, although many potential sites have become rice fields. Similar fish near Trang on the opposite coast have not been conclusively assigned to the same species.

Aquarium setup

Despite its tiny size, provide at least a 45 by 30 cm footprint. Dense planting, floating cover, and branching wood soften the light while leaving swimming room. Dominant males establish temporary spawning territories, so ensure that other individuals can move out of view.

Gentle filtration is preferable to strong current. Use a mature system and avoid sudden changes in water chemistry.

Diet & feeding

Small insects, worms, crustaceans, and other zooplankton are considered likely natural prey. Offer suitable flakes or microgranules alongside daily small live or frozen foods, such as water fleas and brine shrimp, rather than relying exclusively on dried products.

Behaviour & compatibility

A species group or carefully chosen companions of similarly tiny, peaceful fish works best. Keep eight to ten or more to reduce nervousness and encourage male displays. Small freshwater shrimp can share a planted setup. Avoid combining different members of the genus for breeding because hybridization is possible.

Sexual dimorphism

Mature females usually have fuller abdomens, slightly greater size, and less intense color. The anterior flank blotch is distinctly enlarged in males. This sex-linked difference should not be confused with a difference between species.

Breeding

Small egg batches are scattered repeatedly without parental attention. Some offspring may survive in a mature planted aquarium. Controlled breeding uses a separate dim setup with fine plants and a mesh barrier that allows eggs to escape adult access.

Use soft, acidic water toward the warmer end of the normal range and gradually introduce two or three conditioned pairs. Spawning may begin the next morning. Adults eat eggs, so remove them within a couple of days.

Hatching takes about two days, followed by roughly another day of yolk use. Provide microscopic starter foods before progressing to brine-shrimp nauplii or microworms after around a week to ten days. Start small water changes cautiously.

Notes

The fish circulated under provisional names and strawberry-related trade labels before description. Male and female blotch differences are more useful than overall redness when evaluating such labels.