Tell us more about your pond. Width, length, depth.
Pictures of the pond would be welcomed as well!
Questions? Keep asking...plenty of knowledgeable and friendly folks here willing to help out.
Oh, the consensus on koi is that you need at least 1,000 gallons for one koi. If you your pond is smaller and you do have koi, you better have some serious filtration going.
If you do have the need or want to add more fish, check out shubunkins. They don't grow anywhere near the size of koi, and they are beautiful fish. Beautiful colors and long flowing fins. If I had to do it all over again, I would only buy shubunkin.