The Borneo Redline Halfbeak, scientifically named Hemirhamphodon tengah, is a fascinating and visually striking species native to the freshwater streams and peat swamps of Borneo. This species belongs to the family Hemiramphidae, which is known for the distinctive elongated lower jaw that characterizes halfbeaks. Hemirhamphodon tengah is particularly admired for its slender body, accented with a vibrant red line that runs laterally from the tip of the snout to the caudal fin, making it a captivating addition to the home aquarium.

Adapted to the acidic, tannin-rich waters of their natural habitat, Borneo Redline Halfbeaks thrive in aquariums that mimic these conditions. Soft, acidic water, a dark substrate, and the presence of driftwood and leaf litter can help replicate the peat swamp environment, providing the fish with a sense of security and comfort. Dim lighting, achieved through the use of floating plants or a canopy, can further simulate the shaded waters of their native habitat and encourage natural behaviors.

The diet of Hemirhamphodon tengah primarily consists of small invertebrates and insect larvae in the wild. In the aquarium, they should be provided with a variety of live foods such as brine shrimp, daphnia, and mosquito larvae to ensure a balanced diet and maintain their health. While they may accept some high-quality flake foods or frozen foods, live prey is essential for their well-being, particularly for breeding individuals.

Breeding the Borneo Redline Halfbeak can be a challenging yet rewarding endeavor. They are bubble nest builders, with the male constructing a floating nest among plants or under leaves to which the female will lay her eggs. The male then guards the nest and the eggs until they hatch. Maintaining the correct water conditions and providing ample live food are crucial for encouraging breeding behavior and ensuring the health of the fry.

Caring for Hemirhamphodon tengah requires attention to water quality, with regular water changes and careful monitoring of water parameters to maintain the acidic conditions they prefer. Their peaceful nature makes them suitable for community tanks with other similarly sized and tempered species that thrive in soft, acidic water. However, care should be taken to house them with fish that will not outcompete them for food or harass them due to their shy and delicate nature.

In summary, the Borneo Redline Halfbeak is a beautiful and intriguing species that adds both visual appeal and natural behavior to the freshwater aquarium. While their care requires a commitment to recreating specific environmental conditions and providing a diet rich in live foods, the rewards of keeping Hemirhamphodon tengah are significant, offering aquarists the opportunity to observe and care for a truly unique and captivating species.