In a Chinese painting, there are nine koi fish and peony flowers. What's the moral?

Nine is the limit number, taken from the Book of Changes, and nine is the biggest meaning! But nine has a long meaning. In ancient times, these sounds were often different from the same words to express auspicious meanings!

Peony flowers have always meant wealth and good luck, and carp has the word "jade", so the moral of this painting is: peony flowers show wealth, nine carp show fish every year (more than one year), and another meaning is wealth and longevity!

The implication is very auspicious!