Red-tailed Chalceus

Adults can reach 25 cm in length. Their body is elongated, somewhat compressed laterally. The large, deeply forked caudal fin is red. Other fins are typically transparent, but under favorable conditions, they may acquire a reddish tint. Otherwise, the fish does not boast a rich coloration, with dull silver being the dominant color. Sexual dimorphism is weakly expressed — males are almost impossible to distinguish from females. The Red-tailed Chalceus bears a strong resemblance to its close relative, the Yellow-finned Chalceus, but differs from it in its larger size and, as the name suggests, the coloration of its fins.

The species' distribution covers the entire northern part of South America. It can be found in Colombia, Venezuela, Guyana, Suriname, French Guiana, and Peru. It inhabits numerous rivers and their tributaries flowing under the canopy of the tropical forest, preferring to stay closer to the water's surface.

Complex intraspecific relationships dictate the specifics of keeping chalceus: either alone or in a group of at least 6 individuals. With fewer numbers, clashes are inevitable, and weaker fish will be at a disadvantage. It does not get along well with other species, although cohabitation with large characins, cichlids, and catfishes of comparable size is possible. It is strictly incompatible with small fish, which will be perceived as prey.

Keeping Red-tailed Chalceus requires a spacious aquarium of at least 250 liters with large areas of open water. The decor typically includes a sandy substrate, complemented by beech branches and floating plants. However, the choice of decor here is not critically important and can be adapted to the needs of other aquarium inhabitants. Given their diet and the noticeable size of adult specimens, a large amount of waste is produced, so the filtration system must be powerful and is one of the main expenses when setting up. Another important element is a reliable lid to prevent fish from jumping out (they are prone to jumping, especially during feeding) and to eliminate the possibility of injury from sharp edges or burns from lighting lamps. Ideal keeping conditions include weak to moderate current, medium light levels, water temperature of 23–28°C, slightly acidic pH, and low to medium hardness.

This species is carnivorous. In its natural habitat, the diet consists of various insects and crustaceans. In an aquarium environment, they readily accept chopped pieces of shrimp, mussels, earthworms, and flying insects. As a source of essential trace elements, a small amount of dry food (flakes, pellets) may be offered, but it should only serve as a supplement to the main diet. It is worth noting that these fish feed exclusively from the surface and will ignore any food that falls to the bottom.

Cases of successful breeding of chalceus in amateur home aquariums have not yet been recorded. All fish sold are either raised in specialized commercial nurseries or caught in their natural habitat.

A balanced aquarium ecosystem with optimal keeping conditions is the best measure for disease prevention. If signs of illness are detected, such as unusual behavior or rashes on the body, the first step is to check the water quality and parameters. Only after this should treatment begin. Often, simply adjusting the keeping conditions to optimal values is enough to eliminate the problem.

When purchasing, attention should be paid to the integrity of the scales, as this species is prone to losing them during transportation. A healthy specimen should be active, without visible fin damage, ulcers, or film on the body. Avoid fish showing signs of severe stress, manifested by erratic darting around the aquarium or, conversely, complete apathy at the bottom. Since the species is often imported from the wild, it is important to ensure that the fish has started accepting food in the store environment. Keep in mind that chalceus are prone to timidity, so they may appear wary in a display tank but should not show signs of emaciation.