Chilatherina rainbowfish

Adults grow to about 10 cm in length. Males have a blue coloration that smoothly transitions to a silvery-blue hue on the belly. Their lateral line is adorned with a distinct dark blue stripe. Females also exhibit blue tones in their coloration, but these are complemented by brownish-green shades on the back. Along the dark blue lateral stripe, females may show yellow streaks. The dorsal, caudal, and anal fins can also have a yellow sheen. For some time, this species was mistakenly considered a variety of the Fasciata Rainbowfish, as they inhabit the same river systems and share a similar appearance.

The species inhabits rivers on the northern coast of New Guinea, including the Sermowai and Tawarin river basins in Indonesia, as well as water bodies near Wanim in Papua New Guinea. The fish populate sections of rivers with slow currents flowing through tropical forests, where the bottom is covered with a layer of fallen leaves. In their natural habitat, they prefer to stay in deeper areas of water bodies near aquatic vegetation and snags, at water temperatures of 26–30°C and an alkaline environment.

These fish are distinguished by their peaceful and active nature. They feel most comfortable in groups of 6–8 individuals. Chilatherina rainbowfish coexist well with other non-aggressive species of similar size.

For a school of 6–8 fish, the optimal aquarium volume starts from 150 liters. Any composition is acceptable for aquarium decor, the main thing is to provide two different zones: open water for swimming and places for shelter. Natural snags and dense thickets of aquatic plants are perfect for the latter. The fish prefer warm water with medium to high hardness and pH values above neutral. Given that high temperatures are necessary for long-term keeping, it is important to ensure a sufficient amount of dissolved oxygen and regularly maintain the aquarium, preventing the accumulation of organic waste. It is recommended to install an efficient filtration system combined with aeration. Such equipment solves three tasks at once: it maintains low levels of pollution, saturates the water with oxygen, and creates a slight current, imitating the natural conditions of mountain streams. Chilatherina rainbowfish are omnivorous. They readily consume a variety of foods, including live and fresh zooplankton, and can be accustomed to dry foods.

This species is considered omnivorous. These fish accept various foods, including live and fresh zooplankton, and can be quite easily accustomed to dry foods.

No captive breeding of this particular species has been recorded. Rainbowfishes in general spawn readily and to a single pattern: the breeders are fed heavily, spawning mops or fine-leaved plants are placed in the tank for the adhesive eggs, and the mop with the eggs is then moved to a separate container — the adults eat the clutch. Spawning is protracted, repeating day after day in small batches.

Species-specific diseases are not described in the literature, however, as a member of the family Melanotaeniidae, the fish may be susceptible to typical aquarium fish ailments. Common problems include bacterial infections, manifesting as fin damage, and parasitic infestations, accompanied by the appearance of white spots on the body or exophthalmia. Prevention involves maintaining stable water parameters and ensuring quality filtration.

The species is rarely found in general sale, as live specimens are extremely seldom collected for aquaristic purposes. When potentially acquiring, one should assess the fish's overall activity, fin integrity, and the absence of signs of emaciation or skin lesions. It is important to note that any offers for sale require thorough verification of the origin of the specimens due to the rarity of the species and its status in nature.