The Costello Tetra, scientifically known as Hemigrammus hyanuary, is a small and vibrant freshwater fish that hails from the waterways of South America, particularly the Amazon Basin. This species is part of the Characidae family, renowned for including many popular aquarium fish that are celebrated for their beauty and schooling behavior. The Costello Tetra is particularly admired for its subtle yet striking coloration, featuring a translucent body with hints of pink and orange, and a distinctive black mark at the base of its caudal fin, which can vary in intensity among individuals.

Creating an optimal environment for Hemigrammus hyanuary involves replicating the conditions of their natural habitat as closely as possible. This includes a well-planted aquarium with ample space for swimming, as Costello Tetras are active and enjoy being in groups. Adding plants, either live or artificial, provides cover and mimics the densely vegetated areas of their native environment. Additionally, a dark substrate can help to accentuate their natural colors, and driftwood or leaf litter can add to the naturalistic feel, providing hiding spots and contributing to the overall health of the aquarium.

The diet of the Costello Tetra is omnivorous, with a natural preference for small invertebrates and plant matter. In captivity, they should be provided with a balanced diet that includes high-quality flake foods, micro pellets, and live or frozen foods such as brine shrimp, daphnia, and bloodworms. Offering a mix of dietary items ensures they receive all the necessary nutrients for optimal health and vitality.

Breeding Hemigrammus hyanuary can be a rewarding experience, as they are egg scatterers, releasing their eggs among fine-leaved plants or spawning mops. To encourage spawning, a separate breeding tank with soft, slightly acidic water and plenty of plant cover can be beneficial. The fry are small and should be fed infusoria or other fine foods until they are large enough to accept larger fare.

Caring for the Costello Tetra involves regular maintenance to ensure the water quality remains high, with frequent water changes and effective filtration. Their peaceful nature makes them excellent candidates for community tanks, where they can be kept with other similarly sized and non-aggressive fish species. However, their schooling behavior and preference for swimming in groups should be considered when planning tank size and composition to ensure a harmonious environment.

In summary, Hemigrammus hyanuary, or the Costello Tetra, offers aquarists the chance to keep a small, peaceful, and beautifully colored species that adds both movement and visual interest to the freshwater aquarium. While their care requires attention to their dietary, environmental, and social needs, the rewards of keeping Costello Tetras include the enjoyment of their striking appearance and the dynamic presence they bring to the aquatic setting.