The River Murray Rainbow Fish

The River Murray Rainbow Fish, Melanotaenia fluviatilis,is one of the many types of Australian Rainbow fish. This group mainly a tropical and subtropical group of fishes, but this Fish's range extends into warm temperate areas and it is able to take quite low water temperatures.

Origin

The River Murray Rainbow Fish is endemic to Australia. As its name suggests it is found in the River Murray. It is also found in many but not all of the Murray's tributaries and several other river systems and lakes.

Size

They can reach 10 cm (4 inches long), but most are smaller than this. The males tend to be bigger than the females.

Temperature

Most of the articles on the internet about this Fish suggest that a temperature of between 22 and 26 degrees C is ideal for this species. My experience suggests otherwise. Although this is a very versatile fish which will certainly live healthily in an aquarium, being treated as if it were a tropical fish, the specimens with the best colour tend to be pond fish, subject to the natural rise and fall of temperature with the different seasons as well as the different weather.

Water Conditions

This fish is able to take a wide range of conditions. Most of the places it occurs naturally have a high pH and the water is quite hard. In an aquarium I suggest that the pH should be between 6.8 and 8. Excessively soft water is not ideal, but most tap waters will be of a suitable hardness. As with all fish, the Chlorine or Chloramine needs to be removed before it comes into contact with the fish.

Food

This is an omnivorous fish. Like many of its relatives it eats more plant material than most tropical fish. They will live on either Tropical or Goldfish food, but this should be supplemented with vegetable matter. Duckweed (Lemna species) is eaten very readily by this Fish. They also like many types of vegetable. I cook the harder vegetables enough to soften them. Zucchini are eaten as are cucumber, green peas and other vegetables. Like many fish they also relish insect larvae like mosquito larvae, small crustaceans like daphnia, and small worms. Our River Murray Rainbow Fish get frozen blood worms once a week as well as frozen brine shrimp once a week on a different day.