If your koi has ulcers, you need to give antibiotics to your koi. If your koi still have an appetite, consider feeding medicated food.
Koi Remedy Food Kit is all you need to make it.
Though the production and sale of medicated koi food was banned since 2017, you can still buy the ingredients and make it yourself with this Koi Remedy Food Kit.
Plus instead of buying each item separately for the full price, you get 10% OFF by buying them all together as a kit here.
Regular size includes:
Large size includes:
Put 1 lb. of Kodama Koi Food All Season in a bowl.
Dissolve 10 gram (2 teaspoonfuls) Oxolinic acid powder and 1/2–1 oz. Billion Pro Original in a cup of water. First use 1/2 cup of water to dissolve. Then, you can add more water little by little as needed. We do not want the solution too watery nor too pasty.
For the final mixing step, there are two alternate methods:
Lay the food over newspaper at a cool and dry place. The food should become dry after 30–60 min.
Put the food in a large Ziplock bag. Store the food in a cool and dry place. You can store the food in a refrigerator.
Download printable full instructions here:
Instructions for Koi Remedy Food Kit (PDF)