I have a pond in my front yard (small, about 120l) which has had goldfish in it for years - the oldest died recently at around 9 years old, and there are still a couple in there. Until I came on here 18 months ago I had never heard of cycling anything, so had no idea about filters etc, so never got one for the pond, but they seemed to survive all the same, so I assume it just developed all the bacteria growing in there to deal with the ammonia, etc. Now I'm setting up another pond, this time a larger one for feeder fish and plant cultivation, and I'm wondering if it's possible to do the same - namely, make it safe for fish without a filter. Any thoughts on whether that's possible, and if so how to do it? It must be possible since I've done it once, I just don't know what I did the first time! Should I just add water and substrate from my other pond to start the bacteria off? The reason I ask is there is no power point anywhere near where I'm putting it, and it doesn't get enough sun for a solar pump, so thought this might be worth a try. Thanks!