Before buying a new fish, look at it carefully in the dealer's pond.
Even though it may look healthy, bear in mind that dealers are always turning over their stock, making it impossible for you to assess long term health.
This makes a good quarantine facility essential.
Consider keeping the quarantine or medication system live by housing some cheap koi in it continuously.
Their waste will be food for the filter and it makes moving a sick fish from the pond into the system a less stressful experience.
If used to quarantine a new koi, these fish will remove another stress factor by being companion fish for the new arrival.
Always sterilize all equipment, such as nets and bowls, between use in the main pond and the quarantine pond and vice versa.
An effective way of feeding koi regular small portions each day is by using an auto feeder.
These are available in a number of different designs.
They can run on mains electricity, by clockwork or even be solar powered.
Most can be set to deliver an appropriate amount of food at intervals throughout a day.
The on demand type is activated as the fish nudge a rod suspended in the water.
The auto feeder required no power source for its operation.
The body is filled with pellets and suspended above the pond.
When the fish nudge the rod, pellets fall down the tube and onto the water surface.
An internal view shows that the regulator that allows pellets to drop when the rod is moved.
Depending upon type, it may be necessary to experiment with the regulator setting to prevent overfeeding.