The problem is not big. For common diseases, use a whole can of yellow powder, not too much. Let the water turn yellow. Take it once a day for 3-5 days, and it will be effective. Before taking it every day, you must replenish 1 with water. After the fish recovers, leave some old water and replace all the water. The above answers for you. I don't know if you are satisfied. I hope it helps you. If you like ornamental fish very much, and you don't understand some questions, you can add 14450825. Those who love fish pets say fish pie, I am a little fairy who loves fish. Welcome all friends who like to watch fish to join. Well, finally, I wish you success in raising fish.