I have a pond just under 100 gallons in my garden, it has a large external filter with uv and there will be high oxygenation from the spout. The pond is empty at the moment but in the near future we will fill it up and start maturing it, we will wait until the nitrates, nitrites and ammonia have settled off at 0 and then put 3 commons from our other pond in to build up the bacteria. We will then take them out and replace them maybe with 3 or 4 fancy goldfish (im thinking Ryukin Goldfish). There is quite a big temperature fluctuation throughout the day and then it gets very cold in winter, however I have a 150 watt pond heater which will keep the temp (hopefully) above 18c. There diet will consist of vegetables and some insects e.g bloodworms etc. There is some threat from predators e.g herons and cats but we will place a net over it. There will be some big pieces of driftwood and some nice big lillies for cover. Do you think the fancy goldfish will survive? have you had any success with keeping them in a pond?