Don't forget about the Youtube Channel that supports Koivet.com in the mission to educate (especially in time for Spring) when pond fish diseases get out of hand.
Youtube for Fish Medicines, Diseases Symptoms and Cure
Also, don't forget about the book, Dr Erik Johnson's Koi Health and Disease 2
Finally, if you have not seen the section in Koivet about "twenty steps to pond fish health" it's a section of Koivet that takes you "step by step" through an orderly process to lead you to a clear picture of why your fish or pond is "sick" and it starts with water quality. (Video version)
I've uploaded a video that's a favorite of mine, lately. It's about Adding Beneficial Bacteria to Aquariums to speed the cycle. It's an established nitrification system with no break in, over night.