Boraras merah

Adults reach about 2 cm in length. The body is predominantly red with a greyish back. A striking black spot on a reddish background is the main feature of their pattern. Sexual dimorphism is faint: females are usually slightly larger and have a more rounded belly, while males show more intense colour, though this difference is not always obvious.

This fish is endemic to the southern part of Borneo in Southeast Asia. It lives in swamps and in streams flowing beneath dense tropical forest canopy. The natural waters it inhabits are brown-tinted due to high concentrations of tannins released by decomposing organic matter; the bottom is typically covered with fallen leaves, twigs and other plant debris. Today, this species' habitat is seriously threatened by human activity, including palm and rubber plantations, and oil extraction.

This peaceful schooling fish fits well with other small species. Avoid keeping it with large tank mates that could be a threat to such tiny fish. Keep Boraras merah in a group of at least 8–10; in smaller numbers they become shy and will likely spend most of their time hiding.

A school of Boraras merah needs a tank with a footprint of at least 45 × 30 cm, roughly 40 litres or more. The layout should mimic their natural habitat as closely as possible: use sandy substrate, plenty of shade-loving and floating plants, and driftwood. Lighting should be dimmed. To achieve the characteristic brown water of their habitat, add fallen leaves from European trees or exotic ones such as Indian almond leaves and bark. Keeping this species is straightforward and involves standard procedures: a weekly partial water change, regular removal of organic waste (faeces and uneaten food), and stable water parameters. Choose a filter that does not create strong flow, as these fish come from still waters and are not adapted to vigorous currents.

In the wild, these fish feed mainly on small zooplankton. In the home aquarium they readily accept most common foods of appropriate size, whether dry, fresh, or frozen. A daily diet can combine dry flakes or granules with daphnia and brine shrimp. High-protein foods improve their colour and vigour, especially during breeding.

In good conditions with mature males and females present, spawning happens quite often. The fish scatter many eggs that sink to the bottom and receive no parental care. In fact, the parents may eat their own eggs. For this reason, fry rarely survive in the community tank. To preserve the fry, set up a separate 10–15 litre breeding tank with identical water conditions. Equip it with a simple sponge filter, heater, and light. A few shade-loving plants or ferns are sufficient décor. After spawning, gently move the eggs to this tank. The eggs hatch in about two days, and the fry become free-swimming a day later. They then need suitable food: infusoria or powdered fry food are ideal. As they grow, add brine shrimp nauplii to their diet.

Boraras merah is hardy and undemanding. When kept properly, health problems are rare. Illness may occur after injury, contact with sick fish, or significant deterioration in water conditions, such as in a dirty tank or with poor diet.

When buying Boraras merah, check for signs of emaciation and fin damage, as their tiny size makes them sensitive to stress and transport. Healthy fish should be active, show typical schooling behaviour, and display bright, species-typical colour without spots or coating on the body. Avoid fish from tanks where dead fish are visible or where fish show shyness and lethargy, as this species is prone to disease when conditions are poor.