"Carl Beyer" wrote in message
...
I have a small pond (500 gallons). I have been given 2 koi as a gift.
One is 18" the other is around 6. The smaller is a butterfly koi.

Anyway, the butterfly koi seems to swim under the big koi, sort of
hanging in it's shadow.

Just wanted to make sure this is normal, and not something else I need
to worry about.

I would not worry. Behavioral deviancy among koi is extremely rare. :-)