[lildude]

I know some breeds of koi are naturally thin until they reach their mature form, and then they fill out. If I am not mistaken, Matsunosuke sanke does this. Please correct me if I am wrong.

Maybe you have male fish....? Just a thought.

In young fish, I believe you are supposed to look for tale tell signs of good growth and conformation.

For example. Look at the head's width, and then in your imagination, take the width starting at the shoulders you add it length to length and see how many "Head widths" it takes to fill span from the shoulders to the tail stop (odome). If it adds up to 3 lengths, it should have good conformation.

Then, for the entire length of the fish, take the "length" of the fish's head, and then do the same thing you did with the width, only this time, count the head itself. So you start from the tip of the head or you automatically count it as "1", and then keep adding more heads. Until you get 4 lengths down the the tail stop, the conformation should be ok.

I cant remember where I heard this from....
Another thing, I might have my information wrong. Please wait until it can be validated by a more knowledgeable member.

Thank you.
Have a great day.