© Strood and District Aquarist Society HOME home 26. Rhadinocentrus ornatus Regan 1914. Location Seery's Creek

In May 2005 on our third visit to Fischhaus Zepkow, I was able to purchase some of their stock of this beautiful rainbow fish. Little did I know that it would give me so many problems in trying to breed it successfully.

Unfortunately, Ilse & Guido had also had problems which resulted in them producing far more male fish than females. I had two quite small females and a small shoal of large males. There was no way that I could let the females stay with the males as they were far too small and would have been harried probably to death. So the females were grown on in a separate tank for some months before any attempt was made to spawn them. When the females reached around 4cm, I placed a large mop in their tank and added a couple of males.

That seemed to be the first mistake. The males spent more time showing off to one another than attempting to spawn. So, one male was removed and eggs started to appear. Unfortunately, all either fungused or simply melted away.

This indicated that water conditions were not right so I started to replace the hard water with rainwater. This slightly improved the situation in that only some of the eggs fungused or melted away. So I decided to increase the amount of soft water. Being situated mid way between two large oil fired power stations, the rainwater in my storage butt generally is soft but is often very acidic. The pH can be as low as 4.0. Reference to Internet information revealed that this species is usually found in water of pH between 6.0 and 6.5. The use of this water proved to be the key to getting more viable eggs. Eggs stopped melting and fungusing and after 12 days started to hatch. This is where I again had some problems in that the fry seemed to have some difficulties in getting out of the egg case and were then just dying off. The addition of a small amount of liquid fry food produced the necessary bacterial action to soften the egg case and release the fry. Once the fry hatched, it was relatively easy to raise them using the same techniques I normally use for most species of rainbow fish. The fry are slow growing and I guess that it will be the best part of one year before the fry will have matured. Like Ilse & Guido, I too have a preponderance of male fish so the smaller females have to be raised separately.

In the early stages, hundreds of eggs were lost until the water conditions were to their liking. It was indeed a very frustrating time, each day harvesting ten or twenty eggs only to have them fungus or melt away by the next morning. It really was a case of 'try, try, and try again'. The pleasure from the successful breeding and raising of these quite rare fish was immense.

© Pete Cottle 2005. This fact sheet may not be reproduced in any form without the permission of the author.