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Fish Freshwater Care: hard Peaceful

Ornate Rainbowfish

Rhadinocentrus ornatus
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Other names: Soft-spined rainbowfish, Rhadinocentrus, Ornatus
Group: Rainbowfish · Family: Melanotaeniidae · Origin: Australia — coastal heathland (wallum) streams of southeast Queensland and northeast New South Wales

A slender 5–6 cm rainbowfish from the tea-colored, very soft and acidic streams of the eastern Australian coast. Each population has a different color; a collector's species for experienced aquarists.

Will it suit my tank?

Last updated October 16, 2026

Temperature
20–26°C
pH
5.5–7
Hardness
1–8 dGH
Adult size
6 cm
Minimum tank size
60 liters
Social structure
School
Group
at least 6, ideally 10+
Male–female ratio
Dişi ağırlıklı (1 erkek : 2 dişi)
Swimming zone
Middle
Diet
Omnivore
Breeding
Egg scatterer

Water parameters

Temperature20–26°C
pH5.5–7
General hardness (GH)1–8 dGH
Recommended range
May escape, needs a lid Considered shrimp safe Suitable for planted tanks

Overview

October 16, 2026 · Suggest an edit

The ornate rainbowfish is the only species in its genus and lives in the tea-colored, very soft and acidic streams of the sandy coastal heathland (wallum) on the east coast of Australia. Its body is slim and elongated; males show an iridescent blue lateral stripe and fins that lean toward red, blue or orange. Isolated populations differ markedly in color and are usually kept in the hobby under their locality names. It grows to 5–6 cm; because it is sensitive to water parameters, it requires experience.

Tank Setup

October 16, 2026 · Suggest an edit
  • At least 60 liters for a group of 6–10.
  • 22–25°C, very soft and acidic water (pH 5.5–6.5 ideal); using reverse osmosis water and dried leaves/roots is beneficial.
  • A dim layout with dense plants, roots and floating plants.
  • It jumps; use a lid.
  • Hybridization: Different locality forms interbreed and the form's distinctive colors are lost; keep each form separate.

Diet

October 16, 2026 · Suggest an edit

Omnivorous but prefers small live and frozen foods: brine shrimp, cyclops, daphnia and mosquito larvae. It can be supplemented with fine flakes and micro granules.

Behavior and Compatibility

October 16, 2026 · Suggest an edit

Peaceful and somewhat shy; males display to each other with spread fins. It gets along with shrimp and may only eat the young.

Good companions: Small tetras and rasboras that like soft water, blue-eye species, otocinclus, Caridina shrimp.

Avoid: Large and fast fish, fin nippers, species that need hard water.

A short profile for this species

The Ornate Rainbowfish page has the basics, but the sections below have not been written yet. If you keep this species, write a section from your own experience; it will be published under your name after editor approval.

Tank mates

This list is calculated automatically from the species profile and grows as new species are added to the catalog. Try it in the planner for a definite answer.

Usually compatible

Should not be kept together

Hobbyist notes

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Change history and contributors
  1. Page created · October 16, 2026