Purple water time! Spring is a very dangerous time for koi. Bad things can happen very fast. A fish can appear to be just fine on Monday, but be badly infected with ulcers from parasite attacks on Wednesday. Opportunistic parasites multiply very quickly in warmer temperatures, while it takes a bit of time for the koi immune system to fully awaken from the winter cold. This is a major reason why ulcers appear on koi fish most often in early spring. It doesn’t take very long at all for parasites t

Koi fish feeding frenzy