drewry
Fish Herder
how often do you add cold water to stimulate them to spawn
There is a little more to it than just adding cold water.
First of all you need to be sure that you have good adult stock, i.e. adult males and females. ideally 2 males per female. Then they need to be conditioned to bring them into breeding condition. Good food and regular clean water changes. Once in condition a normal water change can trigger a spawning session, but once you have then in top condition a 30 - 40% cool water change may get the going, using water that is around 4º or 5ºC cooler to replace the removed water.
Ian