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| Melanotaenia boesemani - photo© Günther Schmida |
Allen and Cross, 1980
Boeseman's Rainbowfish
Description
In 1980, Gerald R. Allen and Norbert J. Cross described this species collected by a Dutch expedition to West Papua in 1954-55. Working with only preserved museum specimens, Allen and Cross had no idea of the live colouration of this species. However, In November 1982, Allen had the opportunity to collect live specimens during a visit to the remote Vogelkop Peninsula. Heiko Bleher, a well-known fish collector, had accompanied Gerry Allen on the trip and was able to transport a number of live specimens captured during the expedition back to Europe, whereupon they were subsequently bred and distributed in the aquarium hobby.
The colour pattern of male Melanotaenia boesemani is completely different from most other rainbowfishes and show a half-and-half colouration when fully matured. The head and front portion of the body are a brilliant bluish-grey, sometimes almost blackish, with the fins and posterior half of the body largely bright orange-red. Between these two areas, or roughly just behind the pectoral fin, there are alternating light and dark vertical bars. Their wild colouration can fade somewhat in captivity, possibly due to something lacking in the diet.
Females display a broad dark mid-lateral stripe accompanied by a series of narrow yellow or reddish-orange longitudinal stripes corresponding with each scale row, that deepen or lighten according to mood. Mature, older females often show colouration similar to subordinate males, but are usually easily identified by a shallower body/chest depth and smaller, more rounded fin edges.
Distribution
The Ajamaru Lakes region located at the headwaters of the Ajamaru River (Vogelkop Peninsula) which drains into the Kais River, eventually flowing into the Ceram Sea to the south. Found mainly in Lake Ajamaru and a few surrounding tributaries, but it also occurs in Lake Hain and Lake Aitinjo.
Habitat & Ecology
Relatively clear shallow water, with abundant vegetation. The lakes and streams are alkaline with pH in excess of 8.0. Heiko Bleher reported that he initially collected specimens in a small artificial pond constructed by the local natives. The water conditions recorded were reported as pH 9.0, hardness 5° dGH, and conductivity 145 mS. More were later collected from a fast-flowing clear water creek near Ajamaru. Marinus Boeseman reported a pH of 6.4-6.5 when he collected his specimens.
Males are easily distinguished from females by their brighter colours and longer and more elongated dorsal fin rays. May reach a maximum size of 15 cm, but usually less than 10 cm. Males are usually much larger and deeper bodied than females. Spawning females produce between 100 and 200 eggs. Eggs adhere to water plants and hatching occurs around 6-7 days at temperatures between 24 to 28° Celsius.
Remarks
Named in honour of Dr. Marinus Boeseman, Curator of Fishes at the Rijksmuseum van Natuurlijke Histoire of Leiden in the Netherlands and collector of the type specimens. According to labels accompanying the type specimens the native name for this species is 'sekiak' and 'ikan rascado'.
© Copyright Adrian R. Tappin
Updated January, 2007.
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