Sentani Rainbowfish (Chilatherina sentaniensis) 4-5 cm

Overview

The Sentani rainbowfish (Chilatherina sentaniensis) is a beautiful, energetic species prized for its shimmering colours, graceful swimming and lively shoaling behaviour. Offered here at 4-5 cm, these young fish will continue to develop into a striking display fish as they mature, with males typically showing the strongest colour and finnage. Native to the Lake Sentani region of Papua, this species is a superb choice for aquarists looking for a peaceful but active fish that brings movement and sparkle to the upper and middle levels of the aquarium.

Rainbowfish are best kept in groups, and Sentani rainbowfish are no exception. They are social, confident fish that do best when kept in a small shoal, where they feel secure and display more natural behaviour. In the right setup, they are hardy, adaptable and rewarding to keep, making them a great option for experienced beginners and seasoned aquarists alike. As with all live fish from Tropical Fish Co, your order is covered by our live arrival guarantee and fast UK delivery.

These fish are ideal for larger community aquariums with good water quality, open swimming space and plenty of planting. They are not a good match for cramped tanks or aggressive tank mates, but in a well-planned aquarium they can become one of the highlights of the display.

Care at a Glance

Origin & Natural Habitat

Chilatherina sentaniensis originates from the Lake Sentani drainage in Papua, Indonesia. In the wild, rainbowfish inhabit clear, warm freshwater environments such as lakes, streams and connected waterways, often in areas with aquatic vegetation, submerged roots and plenty of natural cover. These habitats are typically well oxygenated and exposed to bright tropical light, which helps explain the species’ active nature and preference for clean, stable water.

Understanding the natural habitat is key to successful care. Sentani rainbowfish are adapted to warm, alkaline to slightly hard water, and they thrive when their aquarium environment mirrors these conditions. They are most comfortable in a mature tank with stable parameters, gentle circulation and plenty of swimming room. A planted aquarium with open areas is ideal, as it allows the fish to shoal, court and display naturally.

Tank Setup & Water Parameters

For a healthy, long-lived group of Sentani rainbowfish, aim for a spacious aquarium of at least 120 litres, with larger tanks preferred for mixed communities or bigger shoals. These fish are active swimmers and appreciate length more than height, so a tank with a generous footprint is especially beneficial. A secure lid is recommended, as rainbowfish can be startled and may jump.

Use a fine sand or smooth gravel substrate and add plenty of live plants such as Vallisneria, Cryptocoryne, Java fern and stem plants. Floating plants can help diffuse light, but leave open swimming space across the front and centre of the tank. Driftwood and rocks can be used for structure, though avoid overcrowding the aquarium. Good filtration and regular maintenance are essential, as rainbowfish are sensitive to poor water quality and sudden changes.

Water should be kept warm, clean and stable, with a temperature range of 24-28°C and pH between 7.0 and 8.5. A hardness of 5-20 dGH is suitable, with slightly harder water often helping the fish show their best condition and colour. Moderate water movement and strong oxygenation are beneficial, but avoid harsh flow that forces the fish to constantly fight the current. Weekly partial water changes are strongly recommended to maintain excellent water quality.

When introducing new fish, acclimate them slowly to reduce stress. Newly imported rainbowfish may be shy at first, but once settled they usually become bold, active and highly visible. Keeping them in a proper shoal helps reduce stress and encourages natural behaviour, including colour display in males.

Feeding Guide

Sentani rainbowfish are omnivores with a strong preference for varied, protein-rich foods. In the aquarium they should be offered a mix of high-quality flake or micro pellet foods, along with frozen and live foods such as daphnia, brine shrimp, mosquito larvae and cyclops. A varied diet supports colour, growth and breeding condition.

Feed small amounts once or twice daily, only as much as the fish will consume in a couple of minutes. Overfeeding can quickly affect water quality, so it is better to offer modest portions and maintain excellent filtration. Occasional vegetable matter or spirulina-based foods can also be beneficial, helping to balance the diet and support overall health.

Juveniles benefit from frequent small meals and a diet rich in fine foods, while adults do well on a mixed feeding regime. If you want to bring out the best colours, regular live and frozen foods are especially useful.

Tank Mates / Compatibility

Sentani rainbowfish are peaceful and generally compatible with other calm community species that enjoy similar water conditions. Good tank mates include other rainbowfish of comparable size, peaceful barbs, danios, larger tetras, rasboras, Corydoras catfish, bristlenose plecs and non-aggressive loaches. They also work well in planted community aquariums with similarly active but non-territorial fish.

Avoid keeping them with aggressive species, fin-nippers or very boisterous fish that may outcompete them at feeding time. Cichlids with territorial behaviour, large predatory fish and overly delicate species are poor choices. Very small fish may be safe in some setups, but should only be mixed with care, as the rainbowfish’s active feeding style can intimidate timid tank mates.

For the best results, keep Sentani rainbowfish in a shoal of at least six, ideally with more females than males if you want to reduce display chasing. A balanced group helps spread attention and encourages confident, natural behaviour. In a well-planted aquarium with compatible companions, they are a lively and peaceful addition to the community.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we specialise in healthy, responsibly sourced aquarium livestock and careful packing for safe transit. Your Sentani rainbowfish will be selected with care and dispatched using fast UK delivery to help minimise stress and get your fish settled quickly into their new home. We also provide a live arrival guarantee for peace of mind, because we want you to buy with confidence.

We understand that live fish are a commitment, which is why we focus on quality, reliable service and clear care information. Whether you are building a planted community tank or adding a standout shoaling species to an established aquarium, Sentani rainbowfish are a superb choice. With the right setup, they reward you with constant movement, elegant displays and vivid colour that improves as they mature.

If you are looking for a peaceful rainbowfish with real presence, Chilatherina sentaniensis is an excellent addition to the home aquarium. Provide space, stable water and a varied diet, and these fish will thrive.