Well its just like kids they like to play, and when its raining they love to play in the rain, they jump alot then.
I have a bunch of small koi and they love to take off paired up in a race across the mud pond, at times they take a flying leap into the air. Small koi are just like kids they are fun to watch playing, you never know what to expect out of them. Who know may be a day a the gym for them LOL.