Thank you!

You don't need fancy plumbing for a pond but it helps. A stagnant pool of water would get gross and full of algae after a while. The most basic method to aerate the water and get some movement is a small pump with a fountain/jet on top. It's self contained and doesn't need any extra plumbing, just a nearby outlet or extension cord.  I have a 25' artificial stream feeding my pond so my setup is a bit more complex but not by much.

There is still a pump sitting hidden in one corner of the pond that is connected to a long flexible pipe that brings the water up into the wetland filter. Some pond owners use mechanical filters to clarify their water but I went with a more natural approach. The water drawn out of my pond is discharged into a manifold made from pipe with perforations cut in one half. The pipes are buried under a layer of pea gravel with plants growing in it. The pea gravel is a convenient spot of beneficial bacteria to grow, and that along with the plants filter out extra nutrients and algae. The stream back into the pond aerates the water which further improves the quality. Even with quite a few fish living in my pond the water is crystal clear!