Ingrid,
Have you ever known of severe storm activity churning up the water and
agitating them into a leap?
wrote in message
...
usual reason for jumping koi at this time of year.... spawning. stubby
tailed ones
can jump higher and further than bttflys. BTW, shelves are one way to
discourage
jumping. the deep the pond the more omph they can gather on the way up.