Koi fish are a great hobby. They also help you to relax and
relieve stress. Koi are particularly fun to watch eat. Although Koi will eat
many natural food sources such as algae and other natural pond residents, the
greatest pleasure for many Koi keepers is in feeding them.
They are truly hogs. They look like piranhas at feeding time,
churning the water, jumping, and I have seen some perform like porpoises,
walking along the water's surface on their caudal fin. Once you hear the sucking
sound of Koi sucking down food you'll never forget it. They remind me of water
polo players who are about to get to the ball when suddenly other players from
behind swim up and over them pushing them under the water. Koi will even swim up
on lily pads to get trapped food.
They are very smart, and can be trained to eat out of your
hand. They are by nature bottom rooting and feeding carp. They quickly learn to
eat floating dry food. The food typically runs $1 to $2 per pound. I have found
floating feeding rings add to the enjoyment. They learn to "hang out" around the
feeding ring.
Any sources of water runoff feeding your pond which could
contain large concentrations of insecticides, herbicides, etc. could be a
serious problem. You would need to control and divert such runoff.
Koi stay healthy by having a large pond to live in. Testing
the water quality for ammonia, nitrites, nitrates, carbonate hardness, salinity,
pH, oxygen concentration etc., is an important and frequent requirement. The
water quality must be kept high.
There are parasites, fungal, viral and bacterial infections to
be sure, but they can be kept under control with good observation and some
testing, such as microscopic examination of skin scrapings, small pieces of gill
tissue, and an occasional autopsy. You may need to hire help in this area.
Most remedies are used in the ppm concentration, so even large
ponds are fairly reasonable to treat. Some sick Koi will require injections.
Fortunately, when they get sick they are easy to catch. Koi are comfortable in
water with around 0.1% salt, which is low enough not to bother most pond plants.
0.3% salt is supposed to keep most parasites under control, but that doesn't
always work as well as some claim, and the higher salt concentration can play
havoc with some pond plants.