Prionobrama filigera

Native to the river basins of South America, the Glass Bloodfin Tetra is a dynamic and hardy species belonging to the Characidae family. In their natural habitat, they inhabit slow-moving streams and tributaries, which informs their preference for a low-flow environment in a home aquarium. Their streamlined, fusiform body shape is a classic adaptation for an active lifestyle, allowing them to swim quickly and gracefully through the water column. As a quintessential schooling fish, they possess a strong social structure and must be kept in groups. A proper school not only reduces stress but also encourages their energetic and fast-swimming behaviors, primarily in the top swimming zone of the tank. Without the security of a group, they can become shy and withdrawn.

Maintaining this species is relatively easy, making it a popular choice. They tolerate a fairly broad spectrum of water parameters, from soft and slightly acidic to moderately hard and more neutral. Consistent warm water temperatures are essential for their health. Their metabolism is efficient, resulting in low oxygen consumption and minimal waste production. This low bioload makes them a forgiving choice for aquarists and a great addition to a well-balanced community ecosystem. Feeding is uncomplicated due to their omnivorous diet. A high-quality flake or pellet food should form the basis of their diet, but they will greatly benefit from the variety provided by frozen, live, and freeze-dried foods. This varied diet helps ensure they receive all necessary nutrients to maintain their health and vitality over their multi-year lifespan. When setting up their environment, consider their top-dwelling nature by providing open swimming space at the surface, with plants and decor arranged to leave this area unobstructed.

Prionobrama filigera, commonly known as the Glass Bloodfin Tetra, is a validated species within the family Characidae, an extensive and diverse family of freshwater fishes in the order Characiformes. Its native range is in South America, where it occupies freshwater habitats characterized by low water flow. Morphologically, P. filigera exhibits a classic fusiform body shape, which is hydrodynamically efficient for its active and sustained swimming behavior. This body plan minimizes drag, allowing for the rapid movements observed in its social schooling activities.

Physiologically, this species is adapted to a stable tropical environment, requiring warm water temperatures. It displays a notable tolerance for a range in pH and water hardness, contributing to its hardiness in captivity. Metabolic assessments indicate a low rate of metabolism, which corresponds with low oxygen consumption and low waste production. This results in a low bioload factor, making it a species with minimal impact on the nitrogen cycle of a closed aquatic system relative to its size. Its diet is categorized as omnivorous, subsisting on a variety of organic matter, small invertebrates, and plant material in its natural ecosystem. Its IUCN Red List status is classified as Least Concern (LC), suggesting that its wild populations are currently stable and not facing immediate threats of extinction. As an active, top-dwelling schooling species, its behavior is fundamentally linked to group dynamics, which is a key consideration for its ethology and welfare in managed environments. Its classification and biological characteristics firmly place it as a typical representative of small, active South American characins.

Breeding the Glass Bloodfin Tetra is considered moderately difficult but achievable for the dedicated hobbyist. This species is an egg-scatterer, and success often requires a dedicated breeding setup separate from the main community tank. Sexual dimorphism is subtle; females are typically fuller-bodied and more robust, especially when conditioned and laden with eggs, while males may appear more slender and streamlined. For a successful spawning attempt, it is recommended to condition a group of well-fed adults together, allowing them to form pairs naturally. A good starting point would be a ratio of at least one male to two females to reduce aggression and increase the chances of fertilization.

The breeding tank should be equipped with soft, slightly acidic water and maintained at the higher end of their preferred temperature range to induce spawning. The inclusion of fine-leaved plants like Java moss or a spawning mop is crucial, as they provide a suitable medium for the adhesive eggs to attach to. Dim lighting can also help encourage the fish to spawn and may improve egg viability. The parent fish should be introduced into the breeding tank in the evening. Spawning usually occurs in the morning, where the pair will swim together, scattering eggs among the plants. It is imperative to remove the adult fish immediately after spawning is complete, as they will readily consume their own eggs. The eggs will hatch within a day or two. The resulting fry are minuscule and will initially feed on their yolk sacs. Once they become free-swimming, they must be provided with microscopic foods such as infusoria, liquid fry food, or microworms. As they grow, their diet can be gradually transitioned to larger foods like newly hatched brine shrimp and finely crushed flake food.