Keeping your pond clean is really important to make sure that the water and the fish stay healthy. If you look after the pond, the fish will look after themselves. So making sure that you remove anything which is dirtying the water or preventing it from entering is a great place to start. A surface skimmer is really useful at constantly removing surface leaves and floating particles as well as keeping the surface free from any foam that may appear. Pond netting spans over the top of the water surface and stops leaves and other garden debris from entering the pond and turning into sludge which can be difficult to remove and allows the build-up of bad bacteria. Nets over the pond will also provide essential protection against herons.
In addition to keeping the pond clean, we also sell some spawning aids which will provide your pond fish somewhere to lay their eggs if there isn't the option of laying them on plants - in a formal koi pond for example. The female will lay her eggs on the spawning aid then the male will fertilize the eggs. If you want to have a go at raising the fry when they hatch you can then remove the spawning aid which the eggs have been laid on. Ensure you have somewhere for the fry to hatch which is big enough and well filtered.