Max Size: 8cm

Ornate Rainbowfish (Rhadinocentrus ornatus)

The enchanting rare Ornate Rainbowfish, Rhadinocentrus ornatus, is relatively popular amongst hobbyists as they are very peaceful, decent-sized, and reasonably hardy as they can adapt to various water conditions.

You can keep Ornate Rainbowfish in a well-planted species-only aquarium or house them with other small and non-aggressive fish in a community aquarium. However, please do not keep them with boisterous or aggressive species as they will have difficulty fending for themselves.

Like other Rainbowfish, these can be pretty skittish and do much better when kept in a shoal of 6 or more as this will encourage the males to display their best colours when they are in the company of their species.

Small, slender, and somewhat elongated, the Ornate Rainbowfish has two rows of black scales along the middle of its flanks. Moreover, they have metallic light blue or red iridescent scales above the lateral line and below the dorsal fin.


Ornate Rainbowfish
Ornate Rainbowfish
Quick Facts
Scientific NameRhadinocentrus ornatus
Other Namessoft-spined sunfish
Aquarium LevelMiddle
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH5.5 - 7.5
GH10 - 20
68 - 82℉
20 - 27.8℃


In the home aquarium, the Ornate Rainbowfish will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements.

Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide additional benefits to your fish's health and well-being but is not a must for this fish.

It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages.

This fish is an omnivore in the wild, meaning it will consume some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Tank Mates

1 interesting tank mate ideas for the Ornate Rainbowfish could include:

Peacock Gudgeon(Tateurndina Ocellicauda)

Sexual Dimorphism

It is relatively simple to differentiate between the male and the female Ornate Rainbowfish. Males are more vibrantly coloured than females and have a long second ray in the second dorsal fin and an elongated anal fin. When in breeding conditions, the males also develop a red stripe that runs from the snout to the second dorsal fin. In contrast, females have shorter fins, have duller colouration, and are usually slightly smaller than males.


Breeding the Ornate Rainbowfish is straightforward once these fish are happily established and settled into your aquarium. You will need a mature pair or group of males and females, along with a spawning mop, preferably floating at the top of the aquarium downwards to the substrate.

Despite spawning year-round, Rainbowfish lay many eggs at the beginning of the rainy season. In addition, temperature increases, and live and frozen foods often encourage spawning.

Check your spawning mops daily for any eggs that have been deposited and either remove the eggs from the mop or, better still, remove the entire mop to avoid contamination of the Rainbowfish eggs.

Tip: Have several spawning mops at hand so you can place a fresh spawning mop into the aquarium while you wait for the eggs to hatch on the other mop/s.

Place the spawning mop with eggs still attached into a separate small cycled aquarium with a sponge filter for flow, and add a few drops of Methylene Blue (Methylene Blue helps prevent fungal infections of eggs).

Your rainbowfish Eggs will hatch within 7 to 18 days, depending on the species and the temperature. We recommend 27°C = 80.6°F for the fastest development of fry.

Once the Rainbowfish fry hatch, they absorb their yolk sacs quickly and become free swimming, moving towards the water's surface. Once the fry reaches the water's surface, you can start feeding. We recommend feeding on Micorworm (the most straightforward live food to culture) and decapsulated brine shrimp egg powder several times a day while being careful not to overfeed and pollute the water column.

After a week or two, you can start to add newly hatched brine shrimp, but this isn't necessary to achieve a high success rate in our experience.

Rainbowfish fry grows slowly, so you should expect to wait several months before the fry is large enough to be added to the adult colony.

Other Rainbowfish of interest

Banded Rainbowfish(Melanotaenia trifasciata)
Boesemans Rainbowfish(Melanotaenia Boesemani)
Celebes Rainbowfish(Marosatherina ladigesi)
Dwarf Neon Rainbowfish(Melanotaenia praecox)
Forktail Blue Eye Rainbowfish(Pseudomugil furcatus)
Honey Blue Eye Rainbowfish(Pseudomugil Mellis)
View all Rainbowfish
Date Added: 25/01/2022 13:33:28 - Updated: 12/08/2022 12:50:23