Van Heurn's Rainbowfish

Adults of this species reach up to 16 cm in length. Their coloration is dominated by yellow tones with a pronounced golden sheen. The back sometimes takes on a brownish, blue, or olive colour with a metallic tint. A broad black-blue band runs along the entire body, bordered by a pale yellow outline. Females are generally less brightly coloured than males and grow somewhat smaller, usually reaching about 10 cm.

This species is native to New Guinea, where it inhabits the basin of the Mamberamo River. It is found in small streams flowing through humid tropical forests, where the water is clear and the bottom consists of stones or sand. Notably, in its natural habitat Van Heurn's rainbowfish lives alongside the well-known aquarium fish Striped rainbowfish.

This is a friendly and active fish that prefers to live in schools, making it necessary to keep it in a group. A school of 6–8 individuals is recommended for a home aquarium. It coexists well with many other aquarium species, including other rainbowfish.

For a group of 6–8 Van Heurn's rainbowfish, an aquarium of at least 150 litres is optimal. The aquarium can be decorated in various ways, but it is important to provide plenty of open swimming space. Natural décor such as driftwood, sand or gravel substrate, and aquatic plants attached to rocks are welcome. Water parameters should be slightly alkaline with appropriate pH; water hardness should be moderate or increased. Avoid the accumulation of organic waste, as this can disrupt the nitrogen cycle. Regular maintenance is essential: weekly partial water changes with fresh water, removal of waste, and checking that equipment, especially the filter, is working properly. Van Heurn's rainbowfish is undemanding with food and readily accepts most popular dried, frozen, and live feeds.

Van Heurn's rainbowfish is not particularly demanding about its diet. It readily consumes a variety of popular feeds, whether dried pellets or flakes, as well as frozen or live options.

There are currently no reliable accounts of successful breeding of this species in captivity. Like other members of the family, it is an egg-scatterer. Mature males develop more intense coloration during spawning, especially around the head. Given the rarity of the species and its natural habitat conditions, successful reproduction requires specific knowledge and conditions that have not yet been described.

The species shows typical rainbowfish sensitivity to water quality, but specific diseases characteristic of this species have not been identified. The main risks are related to deterioration of water parameters, which can lead to weakened immunity and the development of bacterial infections or parasitic infestations. Prevention consists of maintaining stable water chemistry, regular water changes, and providing good-quality food.

Acquiring individuals of this species is extremely difficult due to their rarity in the hobby. When selecting fish, pay attention to their overall activity, fin integrity, and the absence of visible skin damage. Healthy fish should display schooling behaviour and actively respond to food. Avoid purchasing fish showing signs of emaciation, lethargy, or unusual spots on the body, as the adaptation of wild or rare species to captivity requires a high level of owner expertise.