Lake Wanam Rainbowfish Care Guide - Aquarium Setup, Diet & Breeding

Lake Wanam Rainbowfish are elegant, laterally compressed fish with the characteristic deep-bodied profile of the Glossolepis genus. Mature males develop vivid red to orange coloration across the body, often contrasted by darker vertical markings and iridescent blue-green tones around the head and flanks. Females are generally smaller and much more subdued in colour.

They are active, peaceful swimmers that spend most of their time in the middle and upper levels of the aquarium. Males can display to one another by intensifying their colours and spreading their fins, but serious aggression is uncommon when there is adequate space and a balanced group.

In the wild, this species is associated with the clear freshwater environment of Lake Wanam, where it uses shoreline vegetation and submerged structure for shelter and feeding. Its streamlined shape and bright breeding colours reflect the open-water lifestyle common to many rainbowfish.

Lake Wanam Rainbowfish are rarely encountered compared with more widespread rainbowfish species. Their restricted distribution and pressure on their native habitat make them a noteworthy conservation species, and responsibly sourced captive-bred fish are preferable for the aquarium trade.

Lake Wanam Rainbowfish are endemic to Lake Wanam in Morobe Province, Papua New Guinea. Their entire natural range is associated with this highland lake and its connected shoreline habitats in Oceania.

A group should have at least a 120-litre aquarium, with a footprint of approximately 90 × 40 cm or larger; a longer tank is preferable because these are energetic open-water swimmers. Use a secure cover, efficient filtration and generous open swimming space, with plants, roots or smooth rocks arranged around the sides and rear for shelter. A dark, fine-grained sand or fine gravel substrate complements their colours, while moderate water movement and subdued areas created by floating plants can produce a natural-looking setup.

Males can reach about 10 cm (4 in), while females usually remain smaller at approximately 8 cm (3.1 in).

Lake Wanam Rainbowfish are omnivores that feed on small aquatic invertebrates, insect material, algae and other plant matter. Offer a varied diet based on quality flakes or small floating pellets, supplemented with frozen or live foods such as daphnia, brine shrimp, mosquito larvae and bloodworm. Regular vegetable-based foods help provide a balanced diet and support their colour and condition.

Lake Wanam Rainbowfish are generally peaceful community fish and can be kept with other similarly sized, active species such as larger peaceful tetras, danios, rasboras, peaceful barbs, Australian rainbowfish and suitable Corydoras. Avoid slow, delicate or long-finned fish that may be unsettled by their constant activity, as well as large predators and highly aggressive cichlids. Keeping them with other Glossolepis or closely related rainbowfish may result in hybridisation, so separate species are best maintained apart when pure breeding is important.

Lake Wanam Rainbowfish are egg scatterers that can be bred in a separate spawning aquarium. Condition a group with varied, protein-rich foods and provide fine-leaved plants or spawning mops for the adhesive eggs. The fish may spawn over several days, after which the eggs should be removed or the adults separated to prevent them being eaten. Incubation generally takes around one to two weeks, depending on temperature, and the tiny fry require suitably fine first foods.

Males are larger and develop dramatically brighter red-orange breeding colours, with a deeper body and more extended dorsal and anal fins. Females are smaller, slimmer and usually silvery brown or olive with less intense iridescence.