Care
The Lake Wanam Rainbowfish is known only from a small, high altitude lake that is situated in a valley 24km inland from Lae, Papua New Guinea. The lake has a surface area of approximately 3.7km2, with a maximum depth of 20 metres. Water lilies (Nymphaea sp.) and lotus (Nelumbo sp.) are abundant, and the lake is surrounded by steep, grass covered hills. Lake Wanam Rainbowfish are a peaceful shoaling species ideally suited to the planted community aquarium. They should be kept in groups of 6 or more fish, and because of their active nature and moderate adult size, the aquarium should be at least 4ft long to allow them a good amount of swimming space. Filtration should be efficient, but water movement fairly gentle, and frequent partial water changes will help keep nitrate to a minimum - particularly important as this species is sensitive to the build-up of organic wastes. As with many other rainbowfish species, the juveniles can look comparatively drab to the absolutely stunning adult fish, and so are all too often overlooked in the shops. However, once settled into the security of the planted aquarium, these young specimens will soon begin to colour up, revealing their true adult beauty. The males in particular will develop a positively dazzling appearance, with the dominant male displaying the brightest colours of all. Despite their large and deep-bodied adult size, Lake Wanam Rainbowfish will not bother smaller tankmates as their mouths/throats are too narrow to be able to swallow them. Unfortunately, this species is listed as 'critically endangered' on the IUCN redlist of endangered species, largely due to the introduction of non-native, predatory carp and Tilapia, in addition to increased human settlement around the lake. Lake Wanam Rainbowfish are now commercially bred in Germany, and so the specimens you see in the shops will be tank-raised, safeguarding what is left of the wild population.
Feeding
Flake, green flake, micropellets, and small frozen foods such as mosquito larvae, vitamin-enriched brineshrimp, and daphnia.
Breeding
A separate good-sized breeding aquarium should be set up with 75% mature tank water and 25% of dechlorinated fresh water, along with a substrate of marbles. A small air-driven sponge filter (with a mature sponge) should be added to give gentle circulation and filtration, and the temperature set to the high end of the preferred range. A conditioned pair should then be acclimatised across to the breeding aquarium, which should be furnished with plenty of fine-leaved plants/Java moss clumps. After a time, the male will swim in front of the female, displaying the mating stripe on his forehead. He will then begin to drive the female over the plants, utilising the whole length of the tank. The eggs will be scattered over the plants a few at a time. These fish are known as 'continual spawners' which means that the spawning activity takes place over several days, even months in some cases. This can present problems to the aquarist in that some adult fish may begin to consume the eggs as they are scattered. Many fishkeepers have found the eggs to be remarkably tough and have had great success in siphoning them out into another aquarium (containing matching water from the spawning tank). The eggs will usually hatch in 6-9 days (dependent on temperature) and once free-swimming, the tiny fry can be offered infusoria, moving onto larger foodstuffs such as baby brineshrimp and fine crushed flake foods as they develop.
