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| Melanotaenia exquisita [Edith River] - photo© Neil Armstrong |
Allen, 1978
Exquisite Rainbowfish
Description
Body slender and compressed. Two dorsal fins, very close together, the first much smaller than the second. Mature males have a higher first dorsal fin, which overlaps the origin of the second dorsal fin when depressed. Females have smaller rounded dorsal and anal fins. May reach a maximum size of 9 cm, but usually less than 8 cm. Adults are olive on the back and silvery white on the lower half. There is a pair of prominent stripes running along the middle of the side with a red stripe just below. A pair of dark zigzag stripes is situated between the red stripe and base of the anal fin. The dorsal, anal, and caudal fins are edged with red, frequently with small black spots. Males are relatively slender compared to that of most other rainbowfishes.
Distribution
Melanotaenia exquisita was originally collected in 1977 by Gerald Allen and Geoff Evans from the Edith River about 1 km upstream from Lake Malkyullumbo, Northern Territory. The known distribution of Melanotaenia exquisita in the Northern Territory is mainly in upland areas of the Katherine, Edith, Mar, South Alligator, and Fergusson Rivers. Melanotaenia exquisita were believed to occur only in the Northern Territory. However, in 1986 more of these exquisite fishes were discovered in the King George River in the Kimberley region of Western Australia. Then in 1997, another population was discovered by Bruce Hansen et al., in Bindoola Creek, a small stream that flows into the Cambridge Gulf in the far north-eastern area of Western Australia. No doubt other populations will be found in the still untouched northern areas of Western Australia in the future.
Habitat & Ecology
Melanotaenia exquisita typically inhabit small, clear, swift-flowing streams, often congregating in rock pools at the base of small waterfalls such as Jim Jim Falls in the South Alligator system and 17-Mile Falls in the Katherine system (plus the King George Falls in Western Australia). They also occur in the still waters of Lake Malkyullumbo at the base of Edith Falls. Spawning females produce between 100 and 200 eggs, spawning a number of times daily for several days. Eggs adhere to water plants and hatching occurs after 6-7 days.
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| Melanotaenia exquisita [Waterfall Creek] - photo© Günther Schmida |
Remarks
Another rainbowfish species known in the hobby as "Waterfall Creek exquisita" comes from above the Gunlom Falls (also known as UDP Falls or Waterfall Creek Falls), a tributary of the South Alligator River in Kakadu National Park. Permission to collect specimens from this site for whatever purpose is almost impossible to get. However, there are a number of captive populations in existence. Consensus is that this fish may be a new species and not a variety of Melanotaenia exquisita. They differ from Melanotaenia exquisita by having a deeper body and totally different colour. The males show a charcoal black chequer-board pattern over the body with pink edging on the dorsal and anal fins. When spawning the nape band is bright orange. However, we will have to wait until someone in the scientific arena has a good look at the fish before we really know what species it is. Until then it is a good idea not to maintain the different varieties together in the same aquarium as hybridisation may occur.
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| Waterfall Creek |
© Copyright Adrian R. Tappin
Updated January, 2007.
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