Melanotaenia trifasciata [Mary River, NT] - photo© Günther Schmida

Melanotaenia trifasciata

Description
Melanotaenia trifasciata display a great natural assortment of colours. Populations of every river system have their own distinctive body colour and pattern. Consequently, specific names usually based on the locality where each is found are used by aquarium enthusiasts to identify each variety. Males are more brightly coloured, larger, and much deeper bodied than females. They can be recognised by a very deep body, usually deeper than 1/3 of their body length, and an often discontinuous black mid-lateral band.

Distribution
Discontinuous distribution across northern Australia, from the Mary River in the Northern Territory, through Arnhem Land, around the Gulf of Carpentaria to Cape York Peninsula. In north Queensland they are found as far south as the Daintree River. The varieties found in the Pascoe, Claudie and McIvor Rivers in Queensland are more streamlined and do not have the deeper body shape of their counterparts from other river systems. In 1989, some specimens were collected on Melville Island, the only offshore record thus far.

Melanotaenia trifasciata [close-up] - photo© Hristo Hristov

Habitat & Ecology
Melanotaenia trifasciata are tropical fish, and occur in almost every kind of freshwater habitat, from slow-moving streams, wetland swamps, lagoons and clear flowing rivers. They are most common in flowing waters or in streams where water flow is present for much of the year. Frequently found in company with Melanotaenia nigrans and Melanotaenia splendida inornata. Their natural environment is subjected to seasonal variations with water temperatures ranging between 24° Celsius during the dry season and up to 33° Celsius in the wet season. The water is generally alkaline (pH 7.2 - 8.0); however, they are occasionally found in acidic conditions (pH 6.5 - 6.9). They are usually found around sub-surface vegetation, submerged logs, or branches. Melanotaenia trifasciata may reach a maximum size of 15 cm, but usually less than 12 cm, with a body depth of 6-8 cm. Spawning occurs from October to December, with females producing between 100 and 200 eggs, spawning a number of times daily for several days. Eggs adhere to water plants and hatching occurs after 6-7 days.

Remarks
Melanotaenia trifasciata are commonly known as the Banded Rainbowfish or Three-Striped Sunfish. However, I think they should be called the 'Regal Rainbowfish' because they are without doubt the most majestic rainbowfishes you will ever see.

Melanotaenia trifasciata was discovered in June 1895 by the Norwegian zoologist Knut Dahl. The species description was published in 1922 by Hialmar Rendahl, on the basis of one single specimen from the Mary River, in the Northern Territory. Why he proposed the name trifasciata, meaning literally "three-banded", is not very obvious when you look at live specimens. However, It becomes clear when you bear in mind that Rendahl only knew this one museum specimen caught more than 20 years earlier. He described the colours as follows:

"...The ground-colour of the fish is (in spirits) a light brown. Along the sides of the body, occupying the adjacent two-thirds of the scales, there is a broad blackish brown bar on the 5th and 6th longitudinal rows of the scales. ... On both sides, this dark bar is (except on the head) bordered by a very obvious light (in alcohol whitish), bar, the ventral of which is the broadest and about half the width of the dark one..."

© Copyright Adrian R. Tappin
Updated January, 2007.

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Rainbowfishes

Introduction

Scientific Names

Rainbowfish Species