Ornate Rainbowfish - Rhadinocentrus ornatus
Ornate Rainbowfish   -  Rhadinocentrus ornatus

Ornate Rainbowfish - Rhadinocentrus ornatus

The Ornate Rainbowfish was scientifically described by Regan in 1914. Its scientific name is Rhadinocentrus ornatus.

The Ornate Rainbowfish can only reach a length of 6 cm and is therefore a fairly small rainbowfish. Just as the common name suggests, the body is beautifully decorated; dark scale margins create an elaborate pattern over the semi-translucent body. The back and nape of the fish is tinted with sparkling neon blue spangles, and in some specimens you will also be able to see shimmering shades of blue, red or pink.
In many specimens, you will also be able to see a dark stripe on each side of the mid-lateral row of scales. Last but certainly not least, the pelvic, dorsal, anal and caudal fins of the Ornate Rainbowfish are reddish, sometimes with black or blackish rays. In some populations, the fins are purple or blue instead of reddish.

If you purchase Ornate Rainbowfish that hail form blackwaters, they will most likely be much darker than other Ornate Rainbowfishes.

Geographical distribution, habitat and conservation
The Ornate Rainbowfish can be found in streams and lakes near the coast of south-eastern Australia. It lives east of the Great Dividing Range and can be encountered as far north as Waterpark Creek. The typical Ornate Rainbowfish habitat is tannin-stained streams and creeks with little or no flow, and it can also be found in completely stagnant pools and dune lakes. When the Ornate Rainbowfish lives in larger streams, it will normally seek out the calm backwaters. Powerful currents are therefore not recommended in the aquarium. The surrounding environment in this part of Australia is locally known as “wallum” and is really sandy. The water temperature varies from 20-28 degrees C (68-82 degrees F) and the water is acidic, from pH 5.4 to 6.5. In the wild, Ornate Rainbowfish is known to congregate around sunken trees and along vegetated banks. It feeds on insects, larvae, small crustaceans and algae.

The Ornate Rainbowfish has not been evaluated for the IUCN Red List of Threatened Species. It is believed to have been negatively affected by habitat loss, since this part of Australia is the scene for dam building, land clearings and major housing developments. 

Keeping Ornate Rainbowfish in aquariums
The Ornate Rainbowfish is not difficult to keep, but it is not recommended for beginners. Since it is so small it is not a good fish for community setups unless you combine it with really peaceful species that are just as small as this rainbow.

Even a small 30 litre (8 gallon) aquarium is big enough to house six Ornate Rainbowfishes. Try to resemble the natural habitat of the fish when you set up the aquarium and make sure that you include hiding spots and sheltered areas. Wild Ornate Rainbowfish is often found close to sunken trees, along heavily vegetated river banks and hidden among reeds and lily roots. 

The water should ideally be soft. Keep the water temperature in the 23-28 degrees C (73-82 degrees F) range and the water acidic, preferably below pH 6.5.  

The diet should be varied and nutritious. You can for instance use prepared foods as a base and supplement with live meaty foods such as daphnia and small insect larvae. Natural algae growth in the aquarium is also beneficial and can be supplemented with spirulina flakes.   

Breeding Ornate Rainbowfish
The Ornate Rainbowfish readily spawns in aquariums, as long as you provide them with suitable water conditions. Acidic and really soft water is known to increase the chances of spawning. Ideally keep the pH-value in the 6.0-6.5 range and make sure that the total hardness is below 80 ppm. Provide your fish with a suitable spawning medium, e.g. java moss or spawning mops.

In a well decorated aquarium with lots of suitable hiding spots, at least a handful of fry will normally survive. If you want a higher survival rate, move the spawning medium with the eggs to a separate container to avoid predation.

If you keep the water temperature in the 23-28 degrees C (73-82 degrees F) range, Ornate Rainbowfish eggs will normally hatch after 7-10 days. You can feed the fry infusoria and powdered flake food until they are large enough to devour newly hatched brine shrimp.

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Other Australian Rainbowfishes

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