You need to buy a pond book and study from start to finish. You will need everything that you would for a FW tank. Just look at a pond as a large FW tank, only make sure there is an overflow pipe for when it rains so that the water flows out the pipe and not over the pond. Someone I knew did that and she lost all her fish. And do not over feed, over stock and put fish in too early. Bigger pump the better. Lots of circulation is key. Deep is good. Best bet is to read, read, read and read some more. Good books are like $20.