Vietnamese Cardinal

Adult Vietnamese Cardinals reach a modest 2–3 cm in length. They resemble their close relative but are somewhat smaller and differ in colour and body patterning. This species has faint red pigmentation on the dorsal fin, which contrasts sharply with a well-defined white edge. A distinct black stripe runs along the lateral line. Sexual dimorphism is pronounced: males are noticeably more slender, show brighter colour, and have enlarged fins compared to females.

The Vietnamese Cardinal comes from Southeast Asia, specifically from the Ben Hai River basin. There, the natural habitat consists of wide, shallow stream reaches with moderate to fast water flow. The bottom is sandy, and the banks are lined with dense vegetation. Unfortunately, the species is now threatened with extinction and survives in only a few localities. The main cause is the degradation of riparian zones through agricultural activity, particularly rice farming.

These peaceful and friendly fish get along well with most species of similar size and temperament. However, avoid keeping them with territorial, aggressive, or highly active species such as certain barbs.

A school of 8–10 Vietnamese Cardinals needs an aquarium of at least 40 litres. Tank décor is not critical, but observations show that the fish display their brightest colours in densely planted surroundings with a dark substrate and soft lighting. This species makes no special demands on water chemistry, which simplifies maintenance. The key to long-term success is maintaining high water quality and preventing the buildup of organic waste. A good filtration system handles this well. Regular equipment maintenance, weekly water changes and timely substrate cleaning are necessary. Remember that despite their tropical origin, these fish are comfortable at 18–23°C.

Feeding is straightforward. They readily eat most popular commercial foods, whether dry, frozen, or live.

Breeding is not difficult. The fish spawn among fine-leaved plants. In a densely planted tank, adults usually do not eat their eggs or fry, allowing the population to sustain itself without removing the parents. Good water quality and suitable spawning substrate stimulate breeding.

The species has a strong immune system when kept properly. Disease usually results from organic waste buildup or incorrect temperature. Maintain effective filtration and regular water changes to prevent problems. They are most sensitive to overheating above 25°C, which weakens the fish and can trigger bacterial infections.

When buying, look for activity and intact fins. Healthy individuals show bright colour, clear body stripes, and interest in food. Avoid fish showing signs of malnutrition, scale damage, or lethargy, as these indicate stress or hidden disease. It is best to buy a group of 8–10 to reduce stress during acclimation.