Murray River Rainbowfish - Melanotaenia fluviatilis
Murray River Rainbowfish - Melanotaenia fluviatilis

Murray River Rainbowfish - Melanotaenia fluviatilis

The Murray River Rainbowfish was scientifically described by Castelnau in 1878 and its scientific name is Melanotaenia fluviatilis. The fish is not very common in the aquarium trade, especially not outside Australia.

The Murray River Rainbowfish can reach a length of 11 cm (4 inches), but most specimens stay around 8 cm (3 inches). The body of the fish is olive to brownish on the back and upper side. Sometimes these areas can be almost turquoise. The exact colouration is not only depending on locality; the water conditions are also important. The lower half of the fish is whitish. The fins are reddish or clear and can be decorated with pale dots. Between each horizontal scale row you can see a thin brown or reddish stripe, and this stripe is normally extra noticeable in adult males. Some Murray River Rainbowfishes also display a dark mid-lateral stripe, but certainly not all of them.

Geographical distribution, habitat and conservation
The Murray River Rainbowfish is the most southward living of all the Australian Rainbowfish species and lives in the streams of south-eastern Australia. It is found in New South Wales, South Australia and Victoria and can be encountered as south as the River Campaspe and River Goulburn. It is found in many different types of waterways, from streams and drainage ditches to ponds, backwaters, overflows and reservoirs.

The conservational situation seems to be worse for the populations living in Victoria than for other populations of Murray River Rainbowfish. Specimens hailing from Victoria will typically have broader heads with blunter snouts than the other Murray River Rainbowfish populations.

Keeping Murray River Rainbowfish in aquariums

Murray River Rainbowfish
Murray River Rainbowfish
Try to mimic the natural environment of your fish in the aquarium. In the wild, Murray River Rainbowfish appreciates the hiding spots found along grass-covered banks and around submerged trees. You should therefore try to create similar sheltered areas in the aquarium, e.g. by using driftwood and bushy plants. Ideally find out which part of northern Australia your particular specimens come from, since the environment differs a bit depending on geographical location. Murray River Rainbowfish from Victoria can even be kept together with cold water fish since they are exposed to 10 degrees C (50 degrees F) in the wild during the winter. For the other populations, 23-28 degrees C (73-82 degrees F) is recommended. Keep the pH-value from 6.5 to 7.2.

Breeding Murray River Rainbowfish
If you want to coax your Murray River Rainbowfish into breeding, it can be a good idea to mimic seasonal changes in the aquarium. In the wild, the Murray River Rainbowfish is especially keen on spawning during late spring and summer when the water temperature rises above 20 degrees C (68 degrees F) again after the winter. Give your Murray River Rainbowfish plenty of live food to mimic the onset of the warm season. Place java moss, a spawning mop or similar in the aquarium to function as breeding site. The eggs will normally hatch within a week if the water temperature is 25-28 degrees C (77-82 degrees F).You can feed the fry infusoria until they are big enough to eat newly hatched brine shrimp.

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Other Australian Rainbowfishes

Cairns Rainbowfish
Threadfin Rainbowfish
Lake Eacham Rainbowfish
Exquisite Rainbowfish
Slender Rainbowfish
MacCulloch’s  Rainbowfish
Black-banded Rainbowfish
Pygmy Rainbowfish
Western Rainbowfish
Chequered Rainbowfish
Eastern Rainbowfish
Desert Rainbowfish
Banded Rainbowfish
Ornate Rainbowfish