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| Glossolepis wanamensis - photo© Neil Armstrong |
Allen and Kailola, 1979
Lake Wanam Rainbowfish
Description
Generally, the body colour of adult males is an overall greenish colour with a rosy flush on the breast. The anterior scale rows below the lateral line are marked with narrow orange lines becoming green or bluish towards the tail. The upper half of the body often shows a metallic green colouration. The anal fin of the male is very large and elongated reaching a depth of nearly 3 cm. Females are generally a dull greenish colour, have shorter fins and rather drab compared to the males. Males are easily distinguished from females by their brighter colours and the extremely large anal fin.
Distribution
Glossolepis wanamensis is a New Guinea rainbowfish found only in Lake Wanam. Lake Wanam is a circular lake about 3 kilometres in diameter and situated on a small plateau above the Markham River Valley about 30 km west of Lae, Papua New Guinea.
Habitat & Ecology
Found in shallow, clear, sunlit water around sub-surface vegetation, submerged logs, and branches, or among reeds and other shoreline vegetation. The temperature and pH recorded at the lake was 28° Celsius and pH 7.8. Chilatherina fasciata and the introduced African Tilapia species also inhabit the lake. May reach a maximum size of 10 cm SL, but usually less than 8 cm. With a body depth of 4-5 cm, adults become very deep bodied especially the males.
Remarks
C. Ellway first collected this species in 1975 but it wasn't until 1979 that they were scientifically described. This followed their collection by Gerald Allen et al in October 1978. A few live specimens were transported to Australia but failed to become established in the hobby. Barry Crockford brought more live specimens to Australia in 1979. Five survived, which included only 1 female. A year later further live specimens were collected but again only one female survived. This small captive population formed the basis of all the aquarium stock that was available until 1992.
In 1992, Heiko Bleher collected live specimens from the Lake and introduced them to the European hobby. He again collected in 1994 and reported that introduced Tilapia populations had increased dramatically and only managed to collect seven Glossolepis wanamensis males and one female. He returned in 1995 and noted that Tilapia infestation of the Lake had increased even further and only 2 very old male specimens were collected. He reported in Aqua Geögraphia, Volume 16 that Glossolepis wanamensis was becoming extinct in the Lake. However, a more recent survey (1999) by a team from ANGFA, Melbourne Zoo and the Rainforest Habitat in Lae, found that Glossolepis wanamensis were in reasonably large numbers in the Lake, but that a coloured variety of Chilatherina fasciata found in the lake on previous collecting trips had all but disappeared.
© Copyright Adrian R. Tappin
Updated January, 2007.
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