|Melanotaenia arfakensis - photo© Neil Armstrong
Melanotaenia arfakensis have a basic upper body colour that is mauve with silvery reflections, while the lower body (abdomen) is whitish-silver. There is a bluish-black midlateral band that extends from the head to the base of the tail, about one scale wide; and a narrow yellow-orange stripe between each horizontal scale row on the sides of the body. Fins are translucent with a bluish to mauve shading. The second dorsal fin has a dark sub-marginal band and narrow white margins. The caudal fin is a yellowish to translucent white with black upper and lower edge margins. Males may reach a maximum size of 10 cm, but females are usually less than 8 cm. Males are more brightly coloured, larger, and deeper bodied than females.
Distribution & Habitat
Melanotaenia arfakensis were originally collected by Gerald Allen in 1989 from the Prafi River, about 20-30 kilometres west of Manokwari, West Papua. This area is bordered on the western side by the Arfak Mountains. The mountains are a water catchment area for several river systems. A rich diversity of animal and plant life, including tree kangaroos, bandicoots and cuscus, are found here. The Arfak area is important historically and scientifically for being the site of the first extensive zoological expedition to West Papua led by d'Albertis and Beccari in 1872-73.
Melanotaenia arfakensis is currently known from a number of tributaries of the Prafi River system including the Warmare, Aimasi and Nimbai. In addition, they have also been found in several other rivers, namely the Kebar, Nuni, Asiti, Appi and Atai rivers. The pH values in all habitat types were between 7.91 and 8.65. In 2007, they were collected from Supsan Creek, a tributary of Prafi River flowing through palm-oil plantations. The water was clear and slow-flowing over gravel bottom with vegetal detritus and patchy leaf-litter. The water temperature was 25.4°C; pH 7.85 and conductivity 267 ÁS. Their natural environment is subjected to seasonal variations.
Melanotaenia arfakensis is a stream dwelling rainbowfish mainly found around sub-surface vegetation, submerged logs, or branches in small tributary streams, but can also occur in swamps and lagoons. However, their natural habitats are been threatened by logging activities for palm-oil plantations and transmigration settlements.
A number of live specimens were collected by Heiko Bleher in 1990 and are available to the international aquarium hobby.
Allen G.R. (1990) Les poissons arc-en-ciel (Melanotaeniidae) de la Péninsule de Vogelkop, Irian Jaya, avec description de trois nouvelles espèces. Revue française d'Aquariologie 16(4): 101-112.
Adrian R. Tappin
Updated April, 2013