Characidium fasciatum

Adults grow up to 6–7 cm in length. Their elongated body shape resembles some loach species, such as the Chinese Hillstream Loach, the Krano Loach, or Hasseelt's Goby. The predominant color is gray. Depending on the fish's geographical origin, black spots running along a dark horizontal stripe or dashes starting from the back may be found on its body.

The origin of this species is South America. It inhabits the São Francisco River basin and the upper reaches of the Paraná River, located in the eastern states of Brazil. It prefers river sections with sandy-gravel bottoms and moderate currents.

These peaceful and calm fish prefer to stay in groups of at least 6 individuals. They get along well with other non-aggressive species that also tolerate relatively cool water, such as goldfish.

A group of 6–8 individuals will require an aquarium of 80–100 liters. Since these fish prefer the bottom zone, special attention should be paid to the lower tier when decorating the aquarium. Fine gravel or coarse sand will serve as suitable substrate. It is desirable to place stones, boulders, and driftwood to create many shelters. The presence of live aquatic plants is not mandatory. For Characidium fasciatum, it is important to provide a moderate current, which can be achieved with an efficient internal filter. It is also worth remembering that this species tolerates high water temperatures poorly; the optimal temperature range is 18–24°C, which means that in most cases, a heater in the aquarium will likely not be needed. In their natural habitat, they feed on small aquatic invertebrates such as crustaceans, worms, and insect larvae. In home aquariums, their main diet can consist of any sinking dry foods rich in protein, such as flakes and granules.

In their natural habitat, these fish prefer to feed on small aquatic invertebrates such as crustaceans, worms, and insect larvae. In a home aquarium environment, their diet can be successfully based on sinking dry flakes and granules rich in protein. This peaceful and calm fish feels best in a group of at least 6 individuals. They get along well with other non-aggressive species that also prefer relatively cool water, such as goldfish.

Currently, reliable information on breeding Characidium fasciatum in aquarium conditions is practically nonexistent. Due to the rarity of the species in trade, successful reproduction is most often recorded by experienced aquarists working with wild-caught specimens. Creating specific conditions that mimic their natural habitat is recommended, but a generally accepted protocol has not been developed.

The species exhibits relative resistance to diseases when water parameters are maintained. The main health risk is associated with keeping them alone or in unsuitable conditions, which provokes severe stress and reduced immunity. Characidium fasciatum is sensitive to high temperatures and low oxygen content. Prevention includes maintaining water purity, regular water changes, and providing sufficient shelters to reduce stress levels.

When purchasing, pay attention to the fish's activity: healthy individuals should show interest in their surroundings, stay in the bottom layer, and show no signs of emaciation. It is important to avoid specimens with damaged fins, film on the body, or unnatural behavior (lethargy, constant attempts to stay at the surface). Since the species is rare, it is recommended to acquire a group of 6 or more individuals to ensure their social well-being.