Melanotaenia synergos - photo© Gunther Schmida

Melanotaenia synergos

Allen and Unmack, 2008
Batanta Island Rainbowfish

Species Summary
Adult males have a bluish (turquoise) wash above a usually discontinuous mid-lateral stripe and a whitish belly region. They have a gold (yellowish) wash of colour above and below the lateral line near the caudal peduncle. The second dorsal and anal fins are a silver-grey-blue colour. Females are similarly coloured but not as intense and their dorsal/anal fins are uncoloured. They are very similar in colouration, body shape etc., to Melanotaenia catherinae and can easily be confused with this species. The two species share similar meristic and morphological features as well as general colour pattern similarities. However, they differ in modal counts for pectoral-fin rays and lateral scales. They also exhibit slight colour pattern differences related to the width of the dark midlateral stripe, which is generally narrower in Melanotaenia synergos, covering one and a half scale rows for most of its length versus 2 to 3 scale rows for Melanotaenia catherinae. This species should not be confused with Melanotaenia batanta, another rainbowfish found on Batanta Island.

Males are distinguished from females by their brighter colours and longer and more elongated fin rays. Growing to a length of around 10-12 cm, and a body depth of 3.5-4.0 cm, males are usually much larger and deeper bodied than females. I found this species to be reasonably tolerant of the presence of newly hatched fry in their aquarium.

Distribution & Habitat
Melanotaenia synergos is currently only known from Batanta Island, which lies immediately west of the West Papuan mainland. Batanta is a small island approximately 55 kilometres long and 30-35 kilometres wide and is home to three separate species of rainbowfishes. Much of the Island is covered with dense rainforest. They are mainly found around submerged logs, or branches in clear rainforest streams, in water temperatures between 18-28°C. However, their natural environment is subjected to seasonal variations with water temperature, pH, and hardness levels varying considerably.

Melanotaenia synergos - photo© Taoyeah Deng

This species was first collected in 1992 by Heiko Bleher while exploring the freshwaters of Batanta Island. Gerry Allen tentatively identified the species as Melanotaenia misoolensis, which he described in 1982 from a collection held in the Zoological Museum of the University of Amsterdam in the Netherlands. However, as it turns out they were an undescribed species.

In May 2007, Melanotaenia synergos were collected from a small clear-water creek with a sandy and muddy substrate flowing through dense forest on the eastern side of Batanta Island during a survey conducted by the Papuan National Marine and Fisheries Research, the Academy of Fishery Sorong, and the Institut de recherche pour le développement (IRD) Jakarta. Water conditions reported were: Temperature 26.0°C; pH 7.6 and conductivity 467 µS/cm.

Allen G.R. & P.J. Unmack (2008) A new species of rainbowfish (Melanotaeniidae: Melanotaenia), from Batanta Island, western New Guinea. aqua International Journal of Ichthyology, 13 (3-4): 109-120.

Adrian R. Tappin
Updated September, 2015

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