I inherited a koi pond when I bought the property.
I have expanded the planting, and significantly increased the height of the mound behind to incorporate a second, much taller waterfall which is a 'dragon gate fall' or 'carp stone fall'. Water descends onto an upwards pointing rock, representing a salmon swimming against the current. There are many symbolic interpretations of this, but my favourite is that the design reminds us of the importance or remaining true to our own nature, no matter what life throws at us.
In 2020 I removed the net over the pond which provided protection from herons, and replaced it with a trip-wire system - which seems to be working very well.