Melanotaenia grunwaldi
Grunwald’s Rainbowfish
Species Summary
Melanotaenia grunwaldi belongs to the ‘Goldiei’ group of Melanotaenia, a closely related complex of rainbowfishes from southern and western New Guinea that has proven unusually prone to cryptic speciation. Members of the group share broadly similar body shape, meristics and colour pattern, and are most reliably distinguished from one another by genetic differences and their separate, non-overlapping (allopatric) distributions rather than by any single obvious external feature. It was collected in the same 2012 Siriwo River expedition that produced M. bowmani, and again at the Topo River during the same trip back toward Nabire. It is named for Norbert Grunwald of Wuppertal, Germany, a dedicated rainbowfish and blue-eye keeper and breeder who edited the German IRG (Internationale Regenbogenfischgesellschaft) magazine for many years.
Etymology
The species is named in honour of the late Norbert Grunwald, a well-known and highly respected German aquarist who devoted much of his life to captive rainbowfishes and contributed considerable knowledge on their maintenance and biology.
Etymology compiled from C. Scharpf (2022), “Fishes of Sahul: An Etymological Survey (Part 5), the rainbowfishes (continued)”, Fishes of Sahul 36(4): 1968–1992, and etyfish.org.
Distribution & Habitat
Melanotaenia grunwaldi is known from three sites in the upper Wami River system, which rises in hills 15–20 km southeast of the coastal town of Nabire, Papua Province: the Topo River and a nearby tributary at about 193 m elevation, and the Lebki River further inland at 116 m. Fish were taken in moderately fast-flowing water over rock and gravel bottoms.
Description & Comparison with Similar Species
Live adult males are yellow-brown dorsally, greenish brown on the upper back, and whitish below, with a blue mid-lateral stripe and a longitudinal yellow zone immediately above it extending onto the caudal peduncle. Melanotaenia grunwaldi has the largest average eye diameter and longest average predorsal distance recorded for the group, and is its only member usually having 12 rather than 13 or more soft dorsal rays.
In the Aquarium
Melanotaenia grunwaldi does well in a community tank, growing a little larger than M. bowmani (10–12 cm) and showing a lighter, more yellow-orange body colour, though it requires alkaline water and does poorly under acid conditions. It is equally peaceful and easy to breed by the same spawning-mop methods.
Aquarium notes compiled from J. Graf & G. Lange (2016), “Discovering Melanotaenia bowmani and Melanotaenia grunwaldi”, Fishes of Sahul, 30(2): 980–988.
Account compiled for Home of the Rainbowfish from G. R. Allen, P. J. Unmack & R. K. Hadiaty (2016), “The Goldiei group of rainbowfishes from the Birds Neck Region with descriptions of five new species and recognition of Melanotaenia dumasi Weber”, aqua, International Journal of Ichthyology, 22(1): 1–32.
References
- Allen G.R., P.J. Unmack and R.K. Hadiaty (2016) The Goldiei group of rainbowfishes from the Birds Neck Region with descriptions of five new species and recognition of Melanotaenia dumasi Weber. aqua, International Journal of Ichthyology, 22(1): 1-32.