Melanotaenia papuae — photo © Neil Armstrong

Melanotaenia papuae

Allen, 1981

Papuan Rainbowfish

Species Summary

The overall body colouration of Melanotaenia papuae is generally olive-green above the mid-lateral line and silvery white below. A prominent red spot is frequently present on the upper part of operculum. A pair of prominent black lines is present at the upper and lower edge of the lateral line and they continue down the lower half of the body. On the posterior half of the body the colours of these lines become reddish and/or purplish in males and yellow to pale orange in females. The colours and markings of the females are generally less brilliant than those of the males. Named M. papuae after its type locality Papua, the southern portion of Papua New Guinea. Melanotaenia papuae may reach a maximum size of 8 cm, but usually less than 6 cm SL.

Etymology

The species name papuae refers to Papua, the southern portion of Papua New Guinea, where the type locality — a rainforest stream at Mt. Diamond — is situated.

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

The full extent of its geographic range remains undetermined. Most collections have been within a 35 km radius of Port Moresby, Papua New Guinea. They are generally found in rainforest and coastal freshwater streams where they are often found together with Melanotaenia goldiei. Temperature and pH reported from these habitats were 25–33° Celsius and pH 7.3–7.8. From the collections around the Port Moresby District, Gerry Allen found that Melanotaenia goldiei prefers more inland streams which are faster flowing, less turbid, and slightly cooler whereas M. papuae is more often found closer to the coast in quieter conditions. However, in some locations such as the Sogeri Plateau, they are found together, although at this locality M. goldiei was far more abundant.

Remarks

Melanotaenia papuae were one of the earlier New Guinea Rainbowfishes to be maintained in the aquarium hobby and were available in Australia as early as 1961. In 1964, Ian Munro catalogued some specimens from Port Moresby as paratypes of Melanotaenia sexlineata in “Additions to the fish fauna of New Guinea”. However, there was some confusion regarding their correct identification as among Munro's paratypes were some specimens later identified as Melanotaenia papuae by Gerry Allen in 1981. Melanotaenia papuae were collected from tributaries of the Laloki, Brown and Goldie Rivers in 1970 and 1971. Gerald Allen and Brian Parkinson collected about 30 live specimens in 1978 from a small creek at Mount Diamond, about 15 miles west of Port Moresby. Specimens were also collected from the tributaries of the Laloki River in 1981.

Some of these specimens were brought back to Australia and small numbers were distributed in the hobby. They were a very popular species but these days they seem to have been forgotten and are rarely seen.

Melanotaenia papuae — habitat (Port Moresby) — photo © Peter Unmack

Melanotaenia papuae — Laloki River (Sogeri Plateau) — photo © Alan Travers

References

• Allen G.R. (1981) The "maccullochi species group" of rainbowfishes (Melanotaeniidae) with the description of Melanotaenia papuae, new species. Revue française d'Aquariologie 8(2): 47-56.
• Allen G.R. (1991) Field guide to the freshwater fishes of New Guinea. Christensen Research Institute, Madang, Papua New Guinea.
• Berra T.M., R. Moore and L.F. Reynolds (1975) The Freshwater Fishes of the Laloki River System of New Guinea. Copeia 2: 316-326.