There is a black koi in the tank. It has been more than half a year since I returned. It has been healthy. I usually have no problem with group swimming, but there is only one problem: every time I feed this product, I always get to the bottom of the tank to eat residue.What is the problem?The methods of stopping food and feeding liquid food have not worked.When other fish saw me pick up the feed bucket, I grabbed the feed upstream. Every time this product sank directly, it was certain that it was eating debris.Cant figure it out.