ucpondguy - ditto on all of the above. Water quality, water quality, water quality. I've learned alot about health issues - the hard way, of course.

Learning to look past the pattern and develop a better eye. (thanks Tony, Joe, & Brian at Champ!) Learned that if you name your fish they immediately flip over and die. Learned that most koi-keepers are intelligent, (you have to be to keep the daggone things alive!) a little crazy, and generally well-rounded....(and I don't mean body conformation.)