The ornate rainbowfish, Rhadinocentrus ornatus, (also known as the soft-spined sunfish) is a unique and beautiful native freshwater fish found in only a few locations in the Greater Brisbane/Redlands region including the larger sand islands of Moreton Bay, and some patchy distribution through coastal creeks from Byfield, Queensland to Nambucca, New South Wales.
Its distribution has contracted as a consequence of urban and rural development, exacerbated by altered hydrology and water quality. Habitat alteration and urban development are still having negative impacts in several areas. Extensive sampling in rivers and streams of the south-east Queensland mainland over the last few years has yielded relatively few individuals.
The sad tale is that every time we lose a population of ornate rainbowfish from a creek system we are effectively losing a very unique group of fish forever.
In 2010 Wildlife Queensland Bayside Branch commenced a collaborative project to find these beautiful fish. Recent surveys by members of WPSQ Bayside Branch have located three additional populations in the Redland district within a creek system already known to have fish. Hopefully, as more streams are surveyed other populations will be located.
The aim of the project is to save the ornate rainbowfish from extinction by:
1. identifying the location of populations of this species and potential suitable habitat, and
2. raising public awareness about the species and the threats it faces.
In the longer term, the project aims to encourage action that builds resilience into the remaining ornate rainbowfish populations. This will involve supporting efforts, such as captive breeding programs, to ensure the species is protected from extinction.
Just think – you might be lucky enough to have ornate rainbowfish in your local creek!
Whether you know for sure or merely suspect your local fish may be ornate rainbowfish, please contact Wildlife Queensland. We can take a look - and if they are, you will have contributed important data about this rare fish and helped us to secure their long-term survival.
Don’t forget to ask your friends and family if they have seen ornate rainbowfish in their local creeks.
Project resources and information
In Australia four distinct populations of ornate rainbowfish have been identified to date. The four populations occur from Byfield to Fraser Island, Cooloola, Noosa River to Brunswick Heads and south of Brunswick Heads to Nambucca. These populations diverged between two and seven million years ago and so represent long-term divisions and should be considered separate for conservation purposes. 1
It seems every creek system has its own unique population - they certainly vary in colour and potentially could be quite distinct genetically. Ornate rainbowfish can grow to a maximum size of around 7-8 cm in total length, but are usually more common at around 5-6 cm.
Download the factsheet on R. ornatus biology and ecology or factsheet 2 on threats.
You can also download a soft-spined sunfish factsheet from Brisbane City Council.
A detailed account can be read on the Australia New Guinea Fishes Association website.
Read more about our Bayside Branch’s work with the ornate rainbowfish in the article The Beautiful, the Vulnerable and very very small.
Wildlife Queensland Bayside Branch and volunteers from across Brisbane and Redlands are supported by the Brisbane City Council and Redland City Council with valuable technical support from the Australia New Guinea Fishes Association QLD and the consultancy firm frc environmental.
1. Page, T.J., Sharma, S. and Hughes, J.M. (2004). Deep phylogenetic structure has conservation implications for ornate rainbowfish (Melanotaeniidae: Rhadinocentrus ornatus) in Queensland, eastern Australia. Marine and Freshwater Research 55, 165–172.
2. Hancox, D., Hoskin, C.J., and Wilson, R.S. 2010. Evening Up the Score: sexual selection favours both alternatives in the colour-polymorphic ornate rainbowfish. Animal Behaviour 80: 845-851.