Aphyocharax

Adult specimens of this fish grow to almost 6 cm in length. Their coloration can vary from beige to silvery, often with a slight turquoise sheen. The most striking distinguishing feature of the species is its red fins and tail. A related species, Aphyocharax alburnus, has a similar body shape and coloration, but its fins are typically devoid of red hues, which nevertheless does not prevent them from often being confused.

The natural habitat for this species is the Paraná River basin, extending through the southern regions of Brazil, Paraguay, and northern Argentina. In nature, the Red-Fin Tetra is found everywhere in various biotopes, but it particularly prefers areas with calm water, rich in dense aquatic vegetation.

Representatives of this species are peaceful schooling fish, and it is recommended to keep them in groups of at least 6 individuals. With fewer numbers, they may become timid. During the breeding season, males show increased activity, chasing each other to establish a dominant position in the group. However, such activity remains within normal limits and does not escalate into true aggression. They coexist peacefully with other species of comparable size. Good compatibility is observed with other Tetras, small catfish, Corydoras, and Danios, among others.

For a small school of 6–8 Red-Fin Tetras, an aquarium of 80 liters or more will be optimal. It is important to note that for the comfort of the fish, the width and length of the tank are more important than its depth. The decor can be anything, provided there is sufficient swimming space. These fish are known for their hardiness and unpretentiousness. In certain cases, they can even be kept in an unheated aquarium if the room temperature consistently stays above 22–23°C. They adapt well to a wide range of hydrochemical water parameters. Despite their general hardiness, it is important to remember that clean water is vital for all fish, so regular aquarium maintenance and an effective filtration system are essential conditions for their successful keeping.

In a home aquarium, the daily diet will consist of popular types of live, frozen, and dry foods of appropriate sizes. It is recommended to feed the fish several times a day, offering portions that will be completely eaten in approximately 3 minutes.

For successful breeding, it is recommended to use a separate spawning tank of at least 40 liters, with water parameters identical to the main tank. The decor should include low-growing, fine-leaved plants evenly distributed across the substrate surface. An important feature is a high-domed aquarium lid – at least 20 centimeters above the water level. This is because fish may jump out of the water during spawning, but the eggs must fall back in. Fish can breed year-round. Increased feeding with high-protein foods signals the start of spawning. After just one week of such a diet, females become noticeably rounded with eggs. This is the ideal moment to move the females along with the strongest male partner into the prepared spawning tank. After spawning, the adult fish are returned to the community tank.

Health problems in these fish are usually associated with physical injuries or keeping them in unsuitable conditions, which weakens their immune system and, as a result, contributes to the development of various diseases. At the first signs of symptoms, it is necessary first to test the water to rule out exceeding certain parameters or the presence of dangerous concentrations of toxic substances (such as nitrites, nitrates, ammonia). If deviations are found, all parameters should be brought back to normal, and only then should treatment begin.

When purchasing, choose active, mobile individuals with clean scales and no visible fin damage. Avoid fish with pale coloration, signs of emaciation, or unnatural behavior, such as apathy or attempts to stay separate from the group. Note that males have hooks on their anal fin, which can get caught in a net when caught; to avoid injury, the net should be lowered into the water, and the fish allowed to free itself without force.