why my koi ist eating

Question
why would my koi has stop eating for three to four days now and just floats at the bottom of the tank what could be wrong with him? (it's only one out of eleven koi.)

Answer
Hi Jacob;

There are many reasons a fish will stop eating. Stress, injury, infection, water quality, bullying, overcrowding, parasites, inadequate space, etc. Without any information about your tank, your fish and setup I really don't know which it could be. Let me know how big the fish are, what size tank you have them in, how long it has been set up, what kind of filtration, how often you change water, what you feed them and how much food you feed, and most of all, does the sick fish have any physical symptoms such as swelling, spots, buoyancy problems, torn fins, etc. His illness may be the beginning of something all the fish could develop, or it may just be an individual problem. Let me know about the information I asked for and we can go from there...

At Your Service;
Chris Robbins