Oliotius oligolepis

This species of barb is one of the most miniature: adult individuals reach only 4 cm in length. Females, as a rule, are larger than males. Males, although smaller in size, have a significantly brighter and more saturated body coloration. The main shade of their scales is pinkish with a metallic sheen. The surface of the scales is dotted with dark specks, creating a characteristic checkerboard pattern. The fins are red and have a dark edging.

This species inhabits exclusively the island of Sumatra, being endemic to it. It can be found in Lake Meninjau, located in the caldera of an ancient volcano, possibly also in tributary rivers, but the exact boundaries of its distribution remain unknown. It is important to note that all fish currently sold are bred in artificial conditions in commercial aquariums; there are no supplies from the wild.

This fish is peaceful, active, and prefers to stay in schools of 8–10 individuals. Such group behavior not only reduces their timidity but also significantly improves the intensity of their coloration, especially in males, who compete for the attention of females. Checkerboard Barbs get along well with other species of similar size and temperament, including representatives of carp, characin, livebearer, and some catfish species.

The Checkerboard Barb is highly undemanding. For a group of 8–10 individuals, an aquarium of at least 60 L will be sufficient. The tank's decor can be anything, but with certain conditions in mind. It is recommended to use a dark substrate, which effectively highlights the fish's coloration, and to add some floating plants to create natural shading. Various shelters, such as snags, branches, and tree roots, will also be very useful. The equipment set is standard: a filter, heater, aerator, and a low-power lighting system, as the fish prefer subdued light. Special attention should be paid to water quality. Weekly, 25–30% of the water volume must be replaced, and organic waste (food residues, excrement, fallen plant parts, etc.) should be promptly removed using a siphon to clean the substrate.

The diet of the Checkerboard Barb can include all types of food: dry, frozen, and live. The basis of the diet is recommended to be protein components, such as bloodworms, daphnia, and other crustaceans, supplemented with a small amount of dry food with vegetable additives. Feeding should be done 2–3 times a day, offering portions that the fish eat within 5 minutes. All food residues must be removed from the aquarium to avoid water pollution.

Oliotius oligolepis is an egg-laying species. In a home aquarium, spawning can occur in any season. Females lay eggs near the water surface, among plant thickets, while males fertilize them. After this, the eggs are left unattended. Parental instincts in barbs are poorly developed, so they may eat their eggs immediately after spawning. If the goal is to preserve offspring, it is more advisable to breed them in a separate tank — a spawning aquarium. Floating fine-leaved plants such as Myriophyllum aquaticum, Ceratophyllum demersum, Riccia fluitans, and similar ones are placed in it. Eggs caught in this dense plant network are relatively safe. To protect eggs that fall to the bottom, a coarse substrate with large gaps between particles, such as pebbles or decorative glass beads, is used. These voids serve as additional shelter. Recommended equipment includes a heater, aerator, low-power lamp, and a simple sponge filter. The aquarium is filled with water from the main aquarium. When you notice that the females have noticeably rounded, and the males are actively courting their chosen ones, this signals the beginning of the breeding period, and it's time to transfer the future parents to the spawning aquarium. One pair can lay up to 300 eggs. After spawning, the fish are returned to the main aquarium. Fry hatch after 24–28 hours and begin to swim freely after another day. For feeding the fry, it is recommended to use specialized micro-food, which can be purchased at pet stores.

A balanced aquarium ecosystem, providing suitable conditions for a specific species, combined with proper nutrition, serves as the best prevention for various diseases. The emergence of diseases usually indicates an unsatisfactory environmental condition, and this is what needs to be addressed first. However, knowing treatment methods and symptoms of common diseases is also very useful; more detailed information can be found in the section "Diseases of Aquarium Fish."

When choosing Oliotius oligolepis, it is important to consider that under stress conditions, typical for pet store aquariums, the fish's coloration may temporarily fade, becoming gray. A healthy individual should be active and stay in a school, as solitary keeping in a store often provokes timidity or atypical aggression. Avoid buying fish with visible fin damage, film on the body, or signs of emaciation.

• pay attention to the integrity of the scales and the cleanliness of the fins without signs of erosion or white spots;
• choose individuals with clear, non-cloudy eye corneas and no bulging eyeballs;
• ensure there is no rapid breathing or unnatural movements, such as swaying in place or attempting to rub against the substrate and decorations.