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| Melanotaenia gracilis [Drysdale River] - photo© Günther Schmida |
Allen, 1978
Slender Rainbowfish
Description
Body rather slender than most other rainbowfishes and laterally compressed. The lower half of the body has a wash of bright iridescent lavender. Fins are transparent or slightly pink with a bright red border on the dorsal and anal fins, and red tips on the caudal lobes. Closely related to Melanotaenia nigrans, apparently having evolved from a common ancestor. The mid-lateral stripe of Melanotaenia gracilis is not as well defined as that of Melanotaenia nigrans.
Distribution
Melanotaenia gracilis are so far only known from the Drysdale River drainage and nearby Carson River (a tributary of the King Edward River), about 140 km west northwest of Wyndham in the Kimberley region of northern Western Australia. Most collections have taken place in the Drysdale River.
Habitat & Ecology
Located at Australia's northwest corner, the Kimberley region comprises a land area of approximately 421,000 km². Many rivers flow from the high rainfall parts of the northern plateaux to the coastline. The Kimberley region is distinguished by a diverse range of geographical features and much of the region remains intact, undisturbed, and difficult to access. It is a fascinating area and accommodates a number of endemic species, or species which do not occur in the surrounding environment. They are generally found congregating around submerged aquatic vegetation, fallen tree branches etc., in clear, slow-flowing tributary streams.
Mature males are usually much larger and deeper bodied than females. May reach a maximum size of 10 cm, but usually less than 8 cm. Spawning occurs from October to January, with females producing between 100 and 150 eggs. Eggs adhere to water plants and hatching occurs around 7-10 days at temperatures between 24- 28° Celsius. Essentially a carnivore, their natural diet consists of terrestrial insects, small aquatic crustaceans, and insect larvae, with terrestrial insects their primary food source. Aquatic algae, plant pollens, and seeds are also ingested.
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| Melanotaenia gracilis [Drysdale River] - photo© Günther Schmida |
Remarks
Melanotaenia gracilis were first discovered in 1975 by Barry Hutchins from the Western Australian Museum. The first live specimens to be successfully established in the aquarium hobby were collected in 1986 by Ray Leggett and Graham Heidke. Since then there have been numerous collections and they are now reasonably well established.
© Copyright Adrian R. Tappin
Updated January, 2007.
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