|
 |
Chilatherina bleheri - photo© Gunther Schmida |
Allen, 1985
Blehers Rainbowfish
Species Summary
Chilatherina bleheri is a very attractive rainbowfish. They generally have a silvery or bluish-green body colour on the upper back fading posteriorly to pastel shades of yellow to red. The scales on the front half of the body, particularly on the dorsal region, have broad yellow-green margins; the first dorsal fin charcoal grey; second dorsal fin grey suffused with red; caudal and anal fins red; pelvic fins reddish anteriorly with remainder white or translucent; pectoral fins translucent. The lower side of the body is white with a series of faint vertical dark markings. Females lack the vivid red hues and are mainly silvery or pale-bluish grading to grey or greenish-brown. Males display a brilliant yellow-orange stripe on the middle of the forehead during spawning. In addition to the differences in colour pattern and fin lengths between the sexes of C. bleheri, there is also a significant difference in the maximum body depth. Mature males are much deeper bodied than females with older males developing a very deep body. Males may reach a maximum size of 12 cm, but females are usually less than 10 cm. C. bleheri are essentially carnivorous, feeding on a variety of terrestrial and aquatic insects, insect larvae, and small aquatic crustaceans. Aquatic algae and fallen plant pollens are also ingested.
Chilatherina bleheri is most closely related to C. fasciata a widely distributed species inhabiting northern New Guinea in the region between the Markham and Mamberamo Rivers. The two species differ primarily with respect to size of scales and colouration, particularly of mature males. The scale difference is reflected in several counts with C. bleheri invariably having smaller scales and hence higher counts: vertical scale rows - 43 to 50 vs. 39 to 44 for C. fasciata; horizontal scale rows 14 to 16 vs. 11 or 12 and predorsal scales 22 to 25 vs. 18 to 22. The males of C. fasciata lack the red coloration of C. bleheri and often possess a series of dark bars on the lower side above the breast region.
 |
Chilatherina bleheri (spawning) - photo© Gunther Schmida |
Distribution & Habitat
Chilatherina bleheri have been collected from the vegetated shoreline and feeder streams of Lake Holmes (Danau Bira) situated in the Mamberamo region of West Papua. Lake Holmes is a complex of three interconnected lakes lying at an altitude of about 430 metres above sea level and set in the foothills of the van Wees Mountains, approximately 290 km west of Jayapura, the capital city of West Papua. The lakes lie within a radius of 6-7 km with the main lake having a length of approximately 4.5 km and maximum width of about 2 km. The depth appears to be relatively shallow; perhaps averaging less than 5-10 metres. The lakes are drained by a small stream, which flows into the Mamberamo River at a point approximately 15 km directly to the north. Chilatherina bleheri were collected along the heavily vegetated shoreline of the main lakes and also from small, rocky bottom, tributary streams. The lake and surrounding creeks are inhabited by 11 fish species, including one other rainbowfish, Melanotaenia maylandi.
Remarks
Live specimens of this species were initially collected by Gerald Allen and Heiko Bleher in 1982. When first discovered it was thought that they were just another colour variety of Chilatherina fasciata. However, in 1985 they were described by Gerald R. Allen as a new species and named in honour of Heiko Bleher, a well-known fish collector.
Literature
Allen G.R. (1985) Three New Rainbowfishes (Melanotaeniidae) from Irian Jaya and Papua New Guinea. Revue Française d'Aquariologie 12 (2): 53-62.
Adrian R. Tappin
Updated August, 2015
|
