REMEMBER THIS: WATER AND ELECTRICITY DO NOT MIX, SO SAFETY IS THE ORDER OF THE DAY. If you are the least bit uncomfortable working with electrical wiring and devices, then I strongly recommend hiring a qualified electrician.
Just one quick story in that regard. Not long after we had our pond up and running my wife decided she was going to put those little twinkle lights around the perimeter. I didn’t feel that was a very good idea and said so, but of course I didn’t know what I was talking about, so the twinkle lights went into place. One night she discovered they weren’t on so she walked out to the pond to find out why, in her bare feet no less. Her guardian angel was with her that night because as she was checking the lights, part of the string went into the water. Natural reaction. She grabbed them and got the shock of her life. Under those conditions she might have been killed, but most fortunately she is still with me. The only thing killed that night was the idea of twinkle lights around the pond.
Submersible pumps and submersible lights are specially constructed to be used under water. As far as above ground lighting around the pond goes, the Malibu type lights that run off a twelve volt transformer work very well. Remember that everything that will be hooked up to electricity must go through a GFCI (Ground Fault Circuit Interrupter) outlet or breaker. No exceptions. Below are images of the different components. From left to right are a water pump, a UV light, and my own homemade pond filter. Of course all of these components come in different variations.
For ease of information I’m going to tell you how I set up the equipment in our pond, and why I did it the way I did. First the How To Build A Beautiful Backyard Pond