Rhadinocentrus ornatus is a small, graceful rainbowfish from the coastal streams and wallum heath wetlands of south-east Queensland, Australia. It is the only species in the genus Rhadinocentrus and is notable for its preference for soft, acidic to neutral water — quite different from the alkaline preferences of most other Australian rainbowfish. Males are beautifully coloured with a body that shimmers with red, blue, and gold iridescence, and fine, delicate finnage.
This species is adapted to the soft, tea-coloured waters of heath wetland streams, where tannins from leaf litter lower the pH and soften the water. In the aquarium it thrives best in conditions that approximate this — soft, slightly acidic water, subdued lighting, and a dark substrate that reduces stress and enhances colouration. It is more demanding than most rainbowfish and not suitable for hard, alkaline tanks.
Rhadinocentrus ornatus is a Queensland endemic that has experienced some habitat loss and is not as common as it once was. It is well-established in the hobby among Australian native fish enthusiasts and can be sourced from specialist breeders. It breeds readily in soft, slightly acidic water among fine-leaved plants.
