Care
The Madagascar Rainbowfish is known from the lower reaches of the Ivoloina River, the northern terminus of the Canal des Pangalanes (a canal on the east coast that consists of a series of natural rivers, waterways and man-made lakes that extends for over 400 miles/645 km), and as far south as Manambolo Creek, which drains into the Canal des Pangalanes some 10 km south of the town of Vatomandry. Following translocation of the species to marshes near the village of Mahitsy (just north-west of Antananarivo) in the 1950's, it is now also widely established in the Betsiboka basin. The Madagascar Rainbowfish prefers slow-flowing streams that provide shade in the form of dense riparian vegetation. Here, the waters are soft and slightly acidic, and may be clear or tannin-stained. Juvenile fish are typically found in the shallows, with adults frequenting deeper waters.
The aquarium that houses these fish should be as spacious as possible due to their active nature, ideally at least 4ft long. The tank should be aquascaped with areas of dense planting (including floating species) and tangles of driftwood in order to provide plenty of shady hiding places. Filtration should be efficient, but water movement fairly gentle, and frequent partial water changes should be carried out in order to keep nitrate at a minimum. Madagascan Rainbowfish are generally very peaceful and somewhat gregarious, and as such, are best maintained in groups of 10 or more; this will not only make the fish less nervous, but will result in a more effective, natural-looking display. Rival males can sometimes become a little territorial with one another, but this should not be an issue if they are outnumbered by females and there are plenty of visual barriers amongst the decor. Tankmates, if desired, should be of a similar size and temperament. May also be seen on sale as the Madagascan Rainbowfish. Often misidentified in the trade as the congener B. geayi, which is native to the Mananjary River basin further south. Sadly, wild populations of the Madagascar Rainbowfish are in decline due to habitat loss and degradation through siltation caused by deforestation. The introduction of the non-native, predatory Channa maculata during the 1950's has also had a deleterious effect, and they are also vulnerable to piscivorous wading birds. All specimens offered for sale in the trade will be captive-bred.
Feeding
Flake, green flake, micropellets, and small frozen foods such as mosquito larvae, vitamin-enriched brineshrimp, and daphnia.
Breeding
This species has been bred in the home aquarium. A separate good-sized softwater breeding tank should be set up with a small air-driven sponge filter (containing a mature sponge) to provide gentle circulation and filtration. A conditioned group (2-3 females, 1 male) should then be acclimatised across to the breeding aquarium, which should be furnished with plenty of fine-leaved plants/Java moss clumps/spawning mops. After a time, the male will display to a female and will begin to drive her over the plants, utilising the whole length of the tank. The relatively large 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/weeks. This can present problems to the aquarist in that some adult fish may begin to consume the eggs as they are scattered, although this may not be a problem if the adults are kept well fed. However, 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) or else using spawning mops, which, when having caught a number of the eggs, can be moved to a separate tank (again with matching water) and replaced with a new mop, as and when each series of eggs are deposited. The eggs will usually hatch in 7-10 days (dependent on temperature) and once free-swimming, the tiny fry can be offered infusoria, moving onto larger foodstuffs such as baby brineshrimp (Artemia nauplii) as they develop.
