Red-Nosed Rasbora

This very small fish has a graceful, slender body, usually not exceeding 3.5 cm in length. Males are distinguished by the bright orange or red coloration of their head and tail, while their body has a milky-blue hue. In contrast, females are more monochromatic, lacking bright colors; their color varies from silvery to light olive, and their fins are transparent. It is worth noting that the Red-Nosed Tetra from South America has a similar coloration, but these are completely different species that evolved independently on different continents. Males differ from females in head coloration — it is orange or red — and are also typically larger in size.

In 1918, researchers discovered the Red-Nosed Rasbora in Southeast Asia, in the territory of modern Shan State in Burma. In the wild, this fish inhabits the unique mountain Lake Inle and its adjacent swamps, located at an altitude of over 900 meters above sea level. The lake is shallow — only 2–3 meters deep, its surface adorned with “islands” formed by dense intertwining vegetation. These islands serve as shelter and a food source for the fish, which gather in small schools and prefer to stay near such “islands” or along the shoreline, where there is abundant submerged vegetation, such as grass or reeds. During the wet season, the water level in the lake rises, and the fish migrate to nearby bodies of water. Their diet consists of small invertebrates, algae, and various types of zooplankton.

This peaceful species will never be a source of problems in the aquarium. Only other miniature fish are allowed as tank mates. Even calm species larger than 4 cm can cause stress to Rasboras. It is essential to keep them in a school of at least 8 individuals, with the number of males being significantly less than females; an optimal ratio is considered to be 4 females per 1 male to avoid intraspecific skirmishes.

Fish are sensitive to water pollution, so an effective filtration system and regular substrate cleaning are essential. It is recommended to change about a quarter of the water volume weekly. It is advisable to use two heaters — a primary and a backup — to prevent sharp fluctuations in water temperature in case one fails. Rasbora has a narrow temperature range, outside of which it quickly perishes. The aquarium design should mimic its natural habitat: fine sand as a substrate, dense groups of broad-leaved plants arranged to leave enough open swimming space. Floating plants create additional hiding places and dim the light. It is important to avoid using wooden elements, such as snags or branches, as they can release tannins, which these fish do not tolerate.

Breeding Sawbwa in captivity has only recently been successfully mastered; previously, these fish were predominantly caught in the wild. For this reason, they are still poorly acclimated to aquarium conditions and do not always readily accept dry commercial foods, although these can provide a balanced diet. It is recommended to offer live foods, such as daphnia, cyclops, or small bloodworms, in combination with a small amount of high-quality dry food containing vegetable additives (e.g., crushed flakes or pellets).

For breeding, a separate tank will be required, where the future parents will be transferred. A tank of at least 10 liters in volume is suitable, with marbles at least 1 cm in diameter or similar gravel laid on the bottom. Dense thickets of fine-leaved plants are necessary; artificial plants are acceptable, as the water temperature significantly drops during spawning, which not all plants can survive. Equipment needed includes a filter, aerator, and thermometer; a heater will not be necessary. Spawning occurs in February, so in late January, the fish should be fed heavily with meaty food. The male with the brightest coloration and several females with noticeably swollen bellies are transferred to a separate tank, where over 2–3 days, the water temperature is gradually lowered to 15–18°C, and the water hardness should be at least 20 dH (medium hardness). If the room temperature exceeds 18°C, the water can be cooled using a bag of cold tap water, which, tightly tied, is submerged in the tank to gradually lower the temperature. This way, the necessary temperature can be maintained. Spawning will begin within two weeks: the female will start laying eggs in the plant thickets, and the male will fertilize them. It is important that the fish are well-fed so that they do not eat their eggs. After spawning is complete, the fish are returned to the main aquarium. To avoid temperature shock, they should be placed in a plastic bag filled with water from the spawning tank, tied, and placed in the main aquarium to equalize the temperature, and only then can they be released. Fry appear after one day; for the first week, they feed on the remnants of the yolk sac, and then they are able to consume micro-food.

The Red-Nosed Rasbora quickly falls ill when water quality deteriorates, and various diseases are possible. However, with optimal keeping conditions and good nutrition, health problems generally do not arise.

When selecting individuals, attention should be paid to their activity and the integrity of their skin, as this species lacks scales, making them vulnerable to mechanical damage and infections. A healthy fish should exhibit natural schooling activity for the species, rather than hiding in a corner or near the surface. Avoid purchasing fish with signs of emaciation, sunken bellies, or cloudy spots on the body, which may indicate bacterial diseases or protozoan infections. An important indicator of condition is the brightness of their coloration: males should have clearly defined red noses and tail tips, and paleness often indicates severe stress or improper keeping conditions in the store.