The Least Rasbora, scientifically known as Boraras urophthalmoides, is a diminutive and subtly beautiful species of freshwater fish native to the acidic, blackwater streams and ponds of Southeast Asia. This tiny rasbora is a gem for aquarists who appreciate the elegance of more understated fish species.

Featuring a streamlined body that rarely exceeds an inch in length, the Least Rasbora displays a pale, often transparent body with a hint of golden or orange hue along the lateral line and towards the tail. They are marked with one or two dark, almost black spots near the base of the tail, which provide a striking contrast to their otherwise light body color. Their fins are usually clear or have a slight touch of color, adding to their delicate appearance.

In the home aquarium, Least Rasboras thrive in conditions that replicate their natural habitat. They are best kept in soft, acidic water with plenty of tannins, which can be achieved by adding leaf litter and driftwood. These elements not only condition the water but also create a more authentic and comfortable environment for the fish. The aquarium should also be well-planted with areas of dense foliage to provide hiding spots and reduce stress.

Socially, Least Rasboras are very peaceful and are known for their schooling behavior. Keeping them in groups not only enhances their security but also promotes a more natural and engaging display. In a school, their subtle colors become more pronounced, and their collective swimming patterns are mesmerizing to watch.

Diet-wise, Least Rasboras are not demanding but require a variety of small-sized foods to ensure proper nutrition. Fine flake food, small granules, and tiny live or frozen foods such as micro worms or baby brine shrimp are ideal. Offering a mix of these foods helps mimic the diverse diet they would naturally have and supports their overall health and vitality.

Breeding Least Rasboras can be a delicate process due to their small size. They typically spawn among fine plant leaves, where the eggs are somewhat protected. To improve breeding success, it is essential to maintain optimal water conditions and provide a calm environment. Following spawning, it is advisable to remove the adults to prevent them from preying on their eggs or fry.

Altogether, the Least Rasbora is a perfect choice for aquarists seeking a low-maintenance, peaceful, and visually appealing fish. Their modest size and behavior make them ideal for smaller, densely-planted tanks where their beauty and tranquility can be appreciated up close.