My gar is about the same length as yours, I haven't measured him ever since I moved him to the pond. Is it normal for him to change color? i noticed he got very black one day and on another he was very light with spots. Also he isn't eating often at all! Since im not home most of the time i just leave the piece of fish in the pond. Many times it is still there at the end of the day and other times it is gone but i think the koi eat it.