Ornate rainbowfish
Rhadinocentrus ornatus
Also known as Soft-spined rainbowfish, Ornate rainbow
FreshwaterFish
Care at a glance
- Temperature
- 64–82°F
- 18–28°C
- pH
- 5.5–7.0
- Adult size
- 2.4 in
- 6 cm
- Minimum tank
- 20 gal
- 75 L
- Temperament
- Mostly peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Difficulty
- Medium
- Breeding
- Medium
- Rarity
- Rare
- Family
- Melanotaeniidae
- Origin
- Native to coastal southeastern Queensland and northern New South Wales, Australia, in tannin-stained wallum streams, tranquil pools and creeks over sandy substrate.
Overview
Keep a group of at least six in a tank of 75 litres or more at 18 to 28 C with a soft, acidic pH of 5.5 to 7.0. It benefits from a slight seasonal temperature drop in winter to mimic its home range. It is peaceful but small, so pair it with other calm, similarly sized fish rather than boisterous tankmates. Feed small flake, micro pellets and frozen foods such as daphnia, cyclops and brine shrimp.
In the wild
Ornate rainbowfish come from soft, acidic, often tea colored wallum waters that run over sand and past dense marginal plants. Isolated populations have produced a range of color forms, from blue and green to red flushed fish. A planted tank of 75 litres or more with driftwood, botanicals for tannins, fine leaved plants and gentle flow suits them. Soft, acidic water below pH 6.5 keeps them healthiest and most colorful.
Good to know
Rhadinocentrus ornatus is the only species in its genus and a member of the rainbowfish family Melanotaeniidae. Its common name soft-spined rainbowfish refers to the flexible fin spines that separate it from related genera. Because many wild populations are isolated in separate creek systems, keepers often track and keep specific regional color forms pure.
Did you know
Different wallum creeks hold their own distinct color strains, so hobbyists label their fish by location and keep the forms separate to preserve the natural variety.
Weekly picks
Tank mates
Ornate rainbowfish is a mostly peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.
Marble wood shrimp
Atya scabra
Freshwater3.9 in (10 cm) · 20 gal (75 L)73–82°F (23–28°C)
Common whiptail
Rineloricaria parva
Freshwater4.7 in (12 cm) · 20 gal (75 L)68–79°F (20–26°C)
Blue panchax
Aplocheilus panchax
Freshwater3.5 in (9 cm) · 20 gal (75 L)72–82°F (22–28°C)
Paraguay glass tetra
Prionobrama paraguayensis
Freshwater2.4 in (6 cm) · 20 gal (75 L)68–81°F (20–27°C)
Common spiny loach
Lepidocephalichthys thermalis
Freshwater3.1 in (8 cm) · 20 gal (75 L)72–82°F (22–28°C)
Rex halfbeak
Nomorhamphus rex
Freshwater2.2 in (5.5 cm) · 20 gal (75 L)72–79°F (22–26°C)
Common questions
What size tank does an Ornate rainbowfish need?
An Ornate rainbowfish needs at least 20 gal (75 L). It spends most of its time in the middle.
What temperature and pH does an Ornate rainbowfish need?
An Ornate rainbowfish is comfortable at 64–82°F (18–28°C) with a pH of 5.5–7.0.
How big does an Ornate rainbowfish get?
An adult Ornate rainbowfish reaches about 2.4 in (6 cm).
Does an Ornate rainbowfish need a group?
Yes. An Ornate rainbowfish is a schooling species and should be kept in a group, not singly.
Related species
2.4 in (6 cm)20 gal (75 L)73–84°F (23–29°C)Pygmy rainbowfish
Melanotaenia pygmaea
2.4 in (6 cm) · 20 gal (75 L)
2.4 in (6.2 cm)29 gal (110 L)77–86°F (25–30°C)Lake Furnusu rainbowfish
Melanotaenia mairasi
2.4 in (6.2 cm) · 29 gal (110 L)
2.2 in (5.6 cm)24 gal (90 L)75–84°F (24–29°C)Wapoga rainbowfish
Melanotaenia rubrivittata
2.2 in (5.6 cm) · 24 gal (90 L)
2.2 in (5.5 cm)20 gal (75 L)75–86°F (24–30°C)Sahul rainbowfish
Melanotaenia sahulensis
2.2 in (5.5 cm) · 20 gal (75 L)
4.3 in (11 cm)53 gal (200 L)75–82°F (24–28°C)Parkinson's rainbowfish
Melanotaenia parkinsoni
4.3 in (11 cm) · 53 gal (200 L)
2.8 in (7 cm)20 gal (75 L)72–82°F (22–28°C)Dwarf rainbowfish
Melanotaenia maccullochi
2.8 in (7 cm) · 20 gal (75 L)