Melanotaenia fluviatilis; Australian Rainbowfish


Image courtesy New South Wales Government

Scientific Name(s): Melanotaenia fluviatilis

Common Name(s): Australian Rainbowfish

Origin: Hence their name; Australia. Other types of rainbow fish can be found in New Guinea and Irian Jaya as well.

Family: Glossolepis and Melanotaenia

Species Type: Australian Rainbowfish

Maximum Size: 4 inches, 3.5-4.5 inches is typical (9-11cm)

Life Span: 5-8 years when well maintained.

Natural Habitat: Australia; New South Wales and Queensland

Diet: Carnivores; Diet should be varied and consist of Live, insect larvae, crustaceans, worms, insects, and high quality flake or pellets. I personally recommend a high quality staple dite supplemented with live foods.

Temperature: 72-79°F (22-26°C)

PH/Water Chemistry: pH 7-8 (7.2), 5-12 dH

Minimum Tank Size: 29 gallons for a small group is absolute minimum. They are fast swimmers and like lots of space to cruise around the tank.

Tank Region: Middle to upper half of the tank.

Temperament: Peaceful in the community also peaceful with members of the same species.

Possible Tank Mates: Other Rainbowfish, livebearers, tetras, Hatchet fish and other similar sized peaceful fish. I have used them as dither or target fish for small to medium size South and Central American Cichlids.

Filtration and Setup: Being rather low waste producers a UGF, HOB, or sponge filter will do fine with regular maintenance and regular water changes.The tank should be well planted along the back and edges and have open swimming areas. A fine gravel substrate is preferred but a sandy substrate will work as well. Good aeration should be provided as well which can be achieved with a good HOB filter.

Coloration: A laterally compressed elongated species. This species lacks the tall body height characteristic of its genus. The back is yellow-brown while the flanks are silver-brown with a silver to green iridescence. A broad blue band runs from the snout to the caudal fin. This may often be fain in some places. The rear half of the body is marked with several orange-red lateral stripes. The fins, except for the caudal fin, are yellowish with orange-red markings and a dark edge. The caudal fin does not have a dark border. The rear part of the iris of the eye is orange-red as is a marking on the gill cover. Females are less colorful, lacking the orange-red stripes.

Breeding: They are moderately easy to breed. Use a well-planted, tank with temperatures from 75-81°F (24-27°C). Pairing is preceded by vigorous chasing. Spawning usually takes place at dawn and continues for several days. The first day results in 100-200 eggs, with decreasing numbers each day. Eggs are attached to plants by fine threads, these eggs will hatch after 7-8 days. Be sure to feed the parents frequently to reduce the chance of them eating the fry. The young can first be fed paramecia and later Artemia nauplii and freshly hatched brine shrimp as well as finely crushed flake. The fry grow slowly to about .5 inches then growth rate will increase.

Miscellaneous: A very fun fish to keep and very hardy. They are good for the community tank do best if kept in groups of four or more. They also do well with small to medium sized mild mannered Cichlids. The Australian Rainbow is also very adaptive to many conditions.