This could be due to a number of factors – poor water quality, lack of oxygen, parasites and poor nutrition. A food with a high level of stabilised Vitamin C will help build up the immune system and perk up your koi. Also, look for Vitamin E as this helps stress related problems. Soaking the pellets in orange juice will also help. Incorrect nutrition will result in unhealthy koi, regardless of how good the water quality is.
Shirley Aquatics top 10 tips for perfect koi keeping conditions. From koi food and pond plants, to ideal pond filters and pond design! Everything you need to know to make sure you’re giving your pride and koi (sorry) the best possible care.