Question
We have a pond and we brought them inside for the winter.  We believe that one of the koi is sick, we moved him to another tank and put treatment in both tanks, would a baby koi be affected by this treatment Paracide Green?

Answer
The simplest answer is that paracide green will kill parasites.  Baby koi are more susceptible to negative effects than a larger koi would be.  You need to be sure that you are dealing with parasites because if it is a bacteria, you will then need to treat with an anti-bacterial medication.  Every time you add chemicals, you are putting the koi at risk.  Try a salt bath if you are sure there are parasites.  It is usually a more effective treatment.