Do these koi have worms? They have been like this over the winter, started shortly after I fed some tubifex worms. I have over the months treated multiple times with Prazi pro, prazi/metro medicated food and currently feeding metro/focus and garlic guard food. They have had white stringy poo in the past, but now it's sort of chalky off white. But not a lot when I do weekly water changes. I was going to put them in the pond, but I am scared they will infect the whole group. Which would be a disaster. Please any help as to what I should do with them? They are to big for that 55 now. The little one has had this scale less head for ever and never grew.